Greetings,
I am deciding weather to use a poured, or a block foundation wall for an addition. How do they compare… stacked block vs. poured concrete? Any insight is appreciated.
Thanks,
A rear addition provides a small-scale example of how to frame efficiently.
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Replies
Where are you located? That will have much to do with which will work for you
I think ICF the way to go, best of both worlds.two ways to screw up concrete 1) concrete driver 2) concrete finisher
The addition is a 3 season porch in seattle. the space under is non heated storage.
What yer budget?
Cost vary by area, but cheapest to most expensive to have done; block, poured, icf.
Your choice, they all hold up the platform.
your going to get a "chevy vs ford" discussion on this. My view is that it does depend on the situation. Both foundation types can be good, as long as they are done correctly. Block foundations got a bad rap in my part of the country because too many people tryed to get away with 8" block, no pilasters, etc... with 10" block, 12" pilasters in the middle of long runs, and core filled every 4' with rod embedded into the footing - your good.
will this be a basement or crawl space? conditioned or not?
upnorthframer
"If you think education is expensive, try ignorance!!!"
In general I'd say match whatever you have already.
Concrete is stronger than block. If the foundation wall is six feet or more below grade and you have a clay soil,go with concrete. Otherwise block is fine,even block in the above mentioned soil will work if you use 12"block, horizontal and vertical reinforcement. Pilasters on long walls may be needed.
Most foundation walls I have seen are block.Because of hydraulic pressure from wet clay soils can bow a block wall , then concrete is used instead.
mike
stacked block vs. poured concrete?
First off, Greetings and Welcome to the wackiness which is BT.
(Hint, click on your name up in blue, and you can fill in Profile info, which cna help us answer questions.)
Given where you are, not only in the PNWet, but seismic country, your structural engineer may be a better person to ask.
My inclination would be towards ICF, like many of the others here. But, really, any of the choices are about the same, really only differing in detail. The only really critical part is how the sub-surface walls are waterproofed (and the drainage system to keep them that way). Tying into the existing drainage and waterproofing may lead you to the best answer for your specific project.
Reverend GoldenBoy.
Do you have any skills at all? any interest in doing things yourself? The reason I ask is because you can do an ICF wall/foundation so easy. It's really DIY friendly!
Let's start at the beginning.. ICF stands for Insulated Concrete Forms.. Think of them as giant foam leggos.. They go together just about as easy too! They weigh maybe 2 pounds each.. (maybe) they push together like leggo's do and are really easy to do..
Let me give you an example.. I was heavily medicated and my sister-in-law came over and finished the foundation for me.. She had absolutely no construction experiance at all! None!
I think there was one course laid and It took six more courses.. It took her about 4 hours to finish it!
I gave her directions in my drug induced state and I hope I didn't slur my words too badly but she figured it out and did a great job..
Here's the technique.. (readers digest version) you build or have someone build you footings.. then you stack the foam leggos together over the foundation while putting rebar in them and glueing them together with spray foam (great stuff is what I used)
Once they are all in place you put up bracing which is also your walkway. Then you have a pump truck pump concrete into the foam "leggo's which form your walls.
The main advantage other than the ease of doing this is that you have your insulation in place and there are no forms to strip and haul away.
My little foundation I saved over half the cost of the cheapest I could get anyone to do it for me.. from bare dirt to ready to build on I had less than 20 hours of work involved.. (well six hours of mine and 4 hours of my sister-in-law) a whole house might take you about 20 more hours.. (dpending on size and how complex it is)
Two questions.
How many . . . what a minute, can you leave OSB out in the rain for four years? ANd are timber frames cheap? And oh yeah a midget, with a broken back can lay a ICF in 4 hours. LOL!!!!
Seriously I was going to ask, how many guys you need on pour day, and who did the footings? But . . . . Answers welcome, for whatever they might be worth.
I'm thinlking they forgot to turn off his prescription.
Whatever, a guy builds A(singular) house and wants to tell the whole industry how they should do it.
If we all did it his way we'd be out of a job too.
Sooooooooooooooooooo tired of it.
Remodeling Contractor just on the other side of the Glass City
Thanks JHOLE. He sure is good for a great laugh! Love it. ANd laughing my rear off.
Frenchy:
My neighbor had an ICF house built - ICF up to the roof. The contractor f-ed it up pretty good. Started with the HO, who rather than bringing in heavy equipment to clear, brought in a tree company to remove the trees that were in the way and then grind the stumps - well, the above grade part of the stumps anyway. Contractor had a heck of a time digging the footings as there were so many darn roots.... Footers came out pretty shiddy. It was maybe a 3000 sq ft ranch so it was a pretty good sized foundation. Then came the ICF. Some were out of level. Blowouts and bows happened during the pour. Took them something like 6 months to get the foundation and walls in. In the end I sent my trim carp over there who cussed me out because the whole house was so out of wack... He showed me where one wall was 3/4" out of plumb and he was supposed to do built-ins there... HO ended up running out of money so the foundation facing which was supposed to be cultured stone never happened. It's just parged. Looks really good in a half $mil neighborhood.... :-( Luckily there is so many trees you can hardly see the house from the road.
So no, doing ICF isn't exactly like falling off a log.
Edited 1/29/2008 7:54 pm ET by Matt
So no, doing ICF isn't exactly like falling off a log.But you got to remember, they can screw up a plain cheeseburger at micky Dees.two ways to screw up concrete 1) concrete driver 2) concrete finisher
Matt,
I'm surprised that you've never seen anything screwed up before. It does happen you know.. You listed several problems that were improperly dealt with and it wouldn't have mattered what they built the house with since those were so badly screwed up as you pointed out..
I gave the example that my sister-in-law with absolutely no prior construction experianced my foundation with less than a 15 minute drug induced slurred explantation.. So it can be done easily..
There is absolutely no way she could have laid block or poured a wall but she did manage to do a decent job on the ICF's
What do you mean it is not like falling off a log? It only takes four hours to throw one up, then lay your OSB subfloor and let it sit for four years in the rain. Good to go! Then throw and inexpensive timber frame up on top of that. LOL!!!!!!!!!!!!!!
Don't forget the $6 a sq ft (or whatever it was) real stone vaneer!!!
MAtt, I missed that one. Did old frenchy really say that? Of crouse push him on it and he will say, "ah . . ah .. . well they gave the stone away and . . . ah ... my Aunt was out of work, so I . . . ah ... hired her and paid her in kind, ie breakfast each morning" . . . ah . . . ya that's the ticket. LOL!!!!
I saw two friends put in ICF foundations last year. One had a bit of construction experience, the other is a beginner but they are both competant people. They are careful in what they do and they both had the foundations come out straight, square and level. It would have been much harder for them to do it in block or ply forms.
I think ICFs would be the way to go if the OP is a rookie and wants to do it himself. If it's a contract out job, then go with the best bid.
both had the foundations come out straight, square and level. It would have been much harder for them to do it in block
Actually, nothing's easier than laying a straight, square and level block wall - if you dry stack it and surface bond both faces.
Just shim with pennies as necessary. Goes up real quick and almost anyone can do a fine job. The surface-bonded block wall is stronger than a mortared wall and generally doesn't require steel reinforcement. It's also much more water-tight, and can look quite beautiful with the hand-troweled finish.Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
I have to smile when someone says "there's nothing easier than......" . I imagine that you have alot of experience with block. I have done a lot of forming and pouring concrete but I have never even seen a block foundation so I would be reluctant to try one. However, I will keep the possiblity in the back of my mind. Maybe I'll try it one day.
BTW, love the idea with the pennies. It goes along with the Italian tradition of throwing in a couple of coins into any piece of concrete work that we do.
Tell me about surface bonding please.
I've never heard about it...
Marc, Here is one link to get you started. I did it on a barn I built for myself some years back. It is very easy to do. Hardest part was mastering the plastering techniques.
They can't get your Goat if you don't tell them where it is hidden.
DUH. Helps to include the link before hitting post. http://www.thenaturalhome.com/drystackblock.htm
They can't get your Goat if you don't tell them where it is hidden.
Thanks for the link.
I'm hoping not to have to build any more block or concrete walls but it looks like an easy technique.
I have some planters here built simply dry stacking bond beam blocks , dropping in some horizontal bar and filling the cells. Had my then 9 and 12 year old kids do it all after I showed them how. Not the same thing as dry stacking and parging but it also works.
They can't get your Goat if you don't tell them where it is hidden.
I dry stack alot of foundations.
Very easy and fast forms.
After they are all stacked, pour the cores full of pea stone mix. Set the J bolts for the mudsill and start framing a few days later.
I drop #4 bar in every other core, along with the bar that comes out of the footing every 4 cores. Each corner gets a piece as well. Maybe $50 for a decent sized foundation in bar.
Good flat footings is the key here, so long as they are flat stacking doesn't require too much shimming.
A good rubber mallet will move the occasional block that moves in the stacking process.
Cheap forms for a poured wall. That you don't have to strip after the foundation has set up.
We aren't in any seismic area so this passes inspection easily.
Meant to be addressed to all, sorry DT
Woods favorite carpenter
Edited 1/31/2008 6:51 am ET by MattSwanger
No Problem. Makes asking a question easier. Do you use any horizontal bar at all in those walls?
They can't get your Goat if you don't tell them where it is hidden.
I haven't run any horizontal bar yet, in any of the walls.
They don't run it in the mortared walls. They use a wire mesh in the joints. Not sure how well that works. Im no expert but it doesn't seem like it would work all that great. Not enough mud in my mind.
The walls turn out rock solid, with all that peastone in there it will snap off alot of hammer drill bits if you try to attach anything to it. Woods favorite carpenter
Thanks Matt.
They can't get your Goat if you don't tell them where it is hidden.
How do you lay horizontal rebar in a block wall, are there notches in the block for such?
Yes http://www.concretebuildingsupply.com/index.php?page_id=112
They can't get your Goat if you don't tell them where it is hidden.
Tell me about surface bonding please.
Surface-bonding cement, which goes by trade names such as Quickwall and Blockbond, is a fiberglass-reinforced cement that trowels easily and creates a very strong, durable and water-resistant stucco finish on a surface.
In addition to using it for block (CMU) walls, I also use it to build dry-stacked chimneys out of cement chimney block (makes a great finished surface for exposed chimneys, both inside and above the roof), and for protecting and finishing exterior XPS foundation insulation above grade.
For polystyrene board, I cover with 1/2" hardware cloth stapled to the sill and trowel on 1/8" or so of SBC (it comes in either grey or white). Mix the SBC with acrylic modifier for better bonding, elasticity and water-resistance.
For a completely waterproof dry-stacked CMU foundation (I also built composting toilet chambers this way), I surface bond both sides, build up a camfer where the wall meets the footing, and then finish with two coats of latex UGL masonry sealer (also comes in either grey or white).Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Surface Bonding
Shallow, Frost-Protected Foundation
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 1/30/2008 11:06 pm ET by Riversong
I also have uses this method, forgot to mention. Works extreemly well. When it first came out they had a demonstration where they drove a truck into wall to show how strong it was.
Good looking work.
Is there a tradeoff? Cost/performance?
When would it be more appropriate to do a conventional mortar between block?
Is there a tradeoff? Cost/performance?
When would it be more appropriate to do a conventional mortar between block?
Yes, there is a trade-off. It's slower! Surface-applied, fiber-reinforced stucco has been around since the 1970s. It hasn't caught on because it's faster to use mortar than shims to set the blocks level and get them stable (that is, not teetering on crumbs and irregularities in the tops and bottoms of the blocks).
Someone has said that these walls are "stronger" than walls built with mortar. Not exactly. They add nothing to the compressive strength of the wall. How could they? If they aren't carefully shimmed, they would have voids and instability and, thus, probably have less compressive strength.
There's no arguing that an unreinforced block wall laid in mortar has poor tensile strength. I readily agree that a dry-stacked wall that has fibered stucco on the surface has more tensile strength than a mortared block wall without any surface treatment. But, if you apply the fibered stucco to the mortared wall, this difference disappears.
I've used these reinforced stuccos on a few occasions but always on blocks laid in mortar. It's faster for me to use the mortar than to mess with the shims. If you develop basic troweling skills, mortar is a better and faster way to level a course of blocks.
If tensile strength is a concern, I usually use steel and structural grout.
Edited 1/31/2008 5:12 pm ET by Mudslinger
I've never tried one of those dry laid foundations,but it has always seamed like an attempt to get around laying a proper foundation to me.Even for a layman block is not that complicated or difficult and if the situation calls for greater tensile strength you still have the option of stucco.
I for one don't want to try and shim concrete blocks.
Is there a tradeoff? Cost/performance?
If you're a skilled mason, like Mudslinger, you can possibly finish a mortared wall faster than a drystacked wall. But, for the rest of us, dry-stacking is MUCH faster and MUCH easier to get a quality result. And the wall has a finish coat inside and out, has lots of tensile strength even without steel, and is far more water-resistant.
And, contrary to what Mudslinger claims, the occassional shimming takes almost no time at all. Any small voids between blocks get filled when the stucco or parging coat is applied.
SBC is a good deal more expensive than mortar, but it serves several functions and it's less expensive than hiring a mason.
When would it be more appropriate to do a conventional mortar between block?
I would do a conventional block wall only if I had to aesthetically match an existing structure.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 1/31/2008 12:21 pm ET by Riversong
If you're a skilled mason, like Mudslinger, you can possibly finish a mortared wall faster than a drystacked wall. But, for the rest of us, dry-stacking is MUCH faster and MUCH easier to get a quality result. And the wall has a finish coat inside and out, has lots of tensile strength even without steel, and is far more water-resistant.
Again, this material has been around for a half-century--as long as plywood. It hasn't caught on. The builders and masons of America have voted with their wallets against it.
I appreciate you characterizing me as skilled. I'm proud of my masonry skills but I want to emphasize that they weren't acquired in a medieval guild. Masonry skills are available to anyone who's willing to commit to a short, sometimes frustrating period of working with mortar and a trowel. Winston Churhill did masonry around his estate as a hobby. You can speed up the process by enrolling in a masonry class at a local community college.
Edited 1/31/2008 5:07 pm ET by Mudslinger
Again, this material has been around for a half-century--as long as plywood. It hasn't caught on. The builders and masons of America have voted with their wallets against it.
Actually, plywood has been around since ancient Egypt (c. 3500 BC), but it took many thousands of years for it to catch on.
I don't doubt that masons would oppose a system that was different from what they were trained to build and could be done by an amateur. The trades are very conservative.
Plumbers don't like to see compost toilets, either. I had to go twice to the MA Plumbing Board to get even experimental approval for a site-built composting toilet (that's been working beautifully for 10 years).
The Larsen Truss superisulation system that I use never "caught on" either. It was simply too far ahead of its time. It's the way it goes.Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Actually, plywood has been around since ancient Egypt (c. 3500 BC), but it took many thousands of years for it to catch on.
You are a pedant. Like you, I can look up such trivia on Wikapedia. In this case, I was aware that the Egyptians used a form of plywood and that veneer has been used for centuries in furniture making. But what has that to do with this discussion?
My passing remark had to do with the use of plywood in modern light construction. As everybody here knows, plywood didn't come into wide use in residential construction until after WWII. When manufacturers solved the problems related to mass production and quality control (delamination was a persistent problem), it rapidly gained acceptance--due its performance and ease of use.
I don't doubt that masons would oppose a system that was different from what they were trained to build and could be done by an amateur. The trades are very conservative.
Unlike plywood, surface bonding cement has not gained wide acceptance. This is not because masons are "conservative". (Meaning what? That you're "open-minded"?) It hasn't been accepted because it's not that great of a product. You've presented it as some marvelous new system. It's not new and it's not marvelous. It's a system tailored to DIYs. You have grossly over-rated it.
surface bonding cement has not gained wide acceptance. This is not because masons are "conservative". (Meaning what? That you're "open-minded"?) It hasn't been accepted because it's not that great of a product. You've presented it as some marvelous new system. It's not new and it's not marvelous. It's a system tailored to DIYs. You have grossly over-rated it.
I may be a pedant, but you are most assuredly ill-informed and biased.
Surface bonded CMUs are much stronger, more attactive, and more weather-resistant than conventionally mortared walls and have been used in residential and commercial construction, for large municipal water tanks and swimming pools and many other applications.
It is a much faster system to construct (up to 70% more productivity, according to ome source), has six times the flexural resistance of a mortared wall (according to USDA), significantly more uplift resistance, and offers a finished surface.Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
All right, pal, I concede. Surface bonded CMUs are the greatest thing since...composting toilets!
I have never seen or heard of this in my life but i have not been everywhere, One time i saw a guy laying interlocking bricks for a footing though, It met code but i never saw another one.
Some years back I worked a Habitat project in Denver where they used special interlocking blocks that were then "grouted" (core filled) with a concrete pumper. The blocks were pre-colored on the outside, and they had a schedule for rebar horizontally and vertically. Went up very quickly.
If your view never changes you're following the wrong leader
I've used dry stack block with surface bonding cement several times. It has it's place. Most recently (last month) I used it in a situation where 2 outdoor HVAC units (split system, AC part) had to be placed on a somewhat steep hill beside a house. I dug down and created a flat spot and laid solid 4" block right on the ground, then came up from there with 8s creating two ~4' square platforms. Parged the thing with SBC and it was all good. Part of the good was that I was able to parge the block later when I got around to it, and the HVAC guys were able to set their units within a few hours (tops) of when I started.
I have to ask though why surface bonding cement hasn't gained popularity in foundation applications? I mean really, the only place I've seen it used as SOP in a professional environment is for storm sewer boxes - where you often have non-masons building a masonry structure (here looks doesn't count) :-). Even that application was only occasional though... I'm gonna guess the non-popularity is two fold: 1) COST: the material cost of the SBC is somewhat high, considering you don't mix it with sand... Believe me, in low end new construction all ways to save money have been explored, and if SBC was more cost effective I'm sure at least a few of the national builders would have adopted it. Likewise, if it were significantly faster these nationals would have taken notice. 2) APPEARANCE: At least around here a parged foundation is only acceptable on the cheapest of starter homes. Brick veneer is used almost exclusively on masonry CS and basement foundations. Granted sometimes you see poured concrete as a exterior finish on basements, but that's another topic...
So, you make the argument that it's DIY friendly - OK - I'll agree there. Of course that's based on the assumption that time is free. For me, time is one of my most valuable assets - it 'AINT' free!!! BTW - my experience, on a DIY level with it is that there is some material waste involved. Basically, some of it ends up on the ground at the foot of the wall. If I really wanted to DIY a block foundation I'd use it as an opportunity to learn to actually lay block...
As far as SBC being stronger - I really don't know, but I've read what the sales literature says, so it must be. BTW - I've got a really good deal on some water front property in Florida... Interested?
PS - this talk about using ICF for an unheated area is just pure BS. Just laughable!
You arguments about appearance don't hold water because we're comparing an unfinished mortared block wall with a SBC finished wall. In New England, foundations are generally exposed and almost never veneered with brick, including on $ million homes.
And as for the argument about cost, I'm not sure that holds water either. The material costs are certainly higher, but if the labor costs are proportionately reduced then the difference zeros out. However, since the labor costs are less, it would make sense that a mason wouldn't be inclined to sell this option.
As far as SBC being stronger - I really don't know, but I've read what the sales literature says, so it must be.
As I indicated in a previous post, the data on increased strength comes from a study done by the US Dept of Agriculture, not the sales literature.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 2/1/2008 1:19 pm ET by Riversong
Your right - I should have thought of that - the appearance of parged block foundation not being acceptable is a very regional thing.
Another vote for SBC is that the block has to be parged anyway - unless someone is gonna tell me that raw concrete block foundations are perfectly acceptable (appearance wise) in other parts of the country. Don't know - but I'd be surprised.
Other than that, what is your explanation as to why SBC block foundations haven't gained wide acceptance, especially among national builders who always take the cheap way out when it comes to entry level homes...
BTW - I'd be interested in the link of the USDA study on the strength of SBC block and the one that says SBC is 70% faster too. Got data? :-)
Our foundation is simple painted concrete block. Fairly common around here.
If your view never changes you're following the wrong leader
what is your explanation as to why SBC block foundations haven't gained wide acceptance, especially among national builders who always take the cheap way out when it comes to entry level homes...
I thought I already addressed this. Large home builders don't do their own foundations - they sub them out. Masons are not likely to offer a system that makes them less money. All building trades are very conservative. That's why it's taken 35 years since the first oil embargo and fuel price shock for national builders associations to even start talking about efficient and green building.
BTW - I'd be interested in the link of the USDA study on the strength of SBC block and the one that says SBC is 70% faster too.
The 70% increase in productivity came from a manufacturer's literature, but it's consistent with my own experience. The USDA report is at:
http://mha-net.org/msb/docs/surfbond.PDFRiversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
To insinuate that any trades men would reject a building practice based on profit margin shows your naivete. Trades men and masons inperticular are sceptical of new and unproven techniques. This is based in the very real fear that it could cost them significant money. While I do appreciate innovative ideas you would do well to listen to those with more experience and avoid arguing factoids. All tradesmen I know will use what ever method is proven effective and safe, period. will never build a foundation that is not 100% Proven reliable. Your attitude speaks of someone who has not built houses long enough to experience failures or problems. Believe me we all have them and once you do their will be a much softer tone in your voice.
To insinuate that any trades men would reject a building practice based on profit margin shows your naivete. Trades men and masons inperticular are sceptical of new and unproven techniques. This is based in the very real fear that it could cost them significant money.
As you just said, "based on a very real fear that it could cost them money". Same thing I said.
All tradesmen I know will use what ever method is proven effective and safe, period. will never build a foundation that is not 100% Proven reliable.
Not being willing to try something new until it's proven 100% reliable makes certain that nothing new will ever be tried because it cannot be proven reliable until many people try it. Tradespeople are conservative - same thing I said.
Your attitude speaks of someone who has not built houses long enough to experience failures or problems.
I've been bulding houses for more than 25 years, many of them superinsulated houses using materials or technologies that had not received wide acceptance (and still haven't), including rubble-trench and shallow frost-protected foundations, double-wall and Larsen Truss wall systems, dense-pack cellulose insulation, air-tight drywall system, composting toilets, and dry-stacked foundations and other CMU structures.
To my knowledge, every one of my houses is still functioning as designed.
It's because builders like myself employ these materials and methods that they eventually become proven effective and gain wider acceptance.
Most of us are going to do things because "it's the way it's always been done" and some of us are going to be the pathfinders and pioneers who improve the building trades.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
My point exactly you mince words to massage your ego.My meaning of the cost of failures related to the cost to the home owner ( as it relates to there home and investment) and to the builder ( as it relates to their livelihood )in their need to remedy the problem.
These innovative techniques that you some how believe are your own were by and large created by the tradesmen ! Knowledgeble men solving real problems. Most if not all of the "Alternative" building methods were created to deal with specific situations, and therefore have not been deemed optimal for the wider building community. I have lived where double walled construction was born.I have seen the history of shallow frost protected foundations unfold. My opinion ? I think they have a place nothing more.
This was not my point. If I may return to what I was saying-
You are obviously well read and knowledgeable, no denying that.Your presentation is so arrogant that you alienate other knowledgeable tradesmen and craftsmen. There by deprive the rest of us of there input.
Also as someone who has made a life of building and a life of creating a sustainable society, The people on this board are the ones directly building the homes of the future. You make the rest of us tree hugging conservationists unable to reach those with different opinions.
Thanks for your time and patience I have know interest arguing indefinitely so lets let it go at this.
P.S.
Twenty five years is just getting started.We are all learning as we go.
Thanks for the link to the USDA report. A quick glance over of the document shows a date of 1974. Seems like the word would have gotten around by now...
>> Large home builders don't do their own foundations - they sub them out. Masons are not likely to offer a system that makes them less money. <<
Yea - you are right. Subcontractors control national builders....
What is a surface bonded wall exactly?
You say dry stack, no mortar between courses? You must also fill all voids then, right?
What is a surface bonded wall exactly?
Read the rest of the thread - I already explained it and posted pictures.Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Laying block is NEVER easy. At least not on my back.
How are the site conditions - in other words, is it wet or dry or what? Is the soil well drained granular material or silt and clay or what? Block does OK if the site conditions are good. BTW - what is the rest of the foundation made out of? Would the foundation need to be faced with brick or waht?
There is alot of info needed here to answer a question, even one as basic as you are asking.
In any different scenario I would go with either of your choices or ICF, all are good systems when used in thier own strengths, the parameters of design dictate the best choice.
Remodeling Contractor just on the other side of the Glass City
I'm biased, seeing as I set concrete forms for a while when I was a teenager, and love watching concrete flow. ;-) Check out the following link for some ideas on how block walls can fail:
http://www.taunton.com/finehomebuilding/how-to/articles/repair-damaged-concrete-block-foundations.aspx?LangType=1033&ac=fp
That being said, my grandfather laid several block foundations without the benefit of know-how or - to be completely honest - common sense. Forty five years later, all is well, although the house did have to be excavated to be properly waterproofed.
Much seems to depend on personal or contractor preferences in you area.
Myself: -no experience with ICF
- Block: looks nicer, but still not great
easier to modify,add on to
with care, can be laid w/o much experience with decent results
-Poured: much stronger
We fully backfill all but very long walls before framing, makes access
much easier for framing & materials. This reason alone makes
poured walls my choice
cost is very close in my area
now here is my ideas. block wall tend to be stronger. How might you ask, they are built in factory. In a factory setting you don't have to worry about too much water or sand. This can make an onsite pour challenging. I have seen collapsed concret walls in clay, hard to drain soil. The problem today, is that laying blocks is hard work. there doesn't seem to be enough masons coming along. ICF, can be good but must be well braced or you can lose the wall during the pour. NOW that i have given my oppoion, they are like ah... everyboy has one.
I have done a lot of both, i use blocks more, Why??? Because i dont have forms and by the time i build the forms i have a lot of blocks up. i learned how to lay blocks young, Here on the coast all the carpenters build forms and pour concrete and say its stronger but i think the blocks are stronger, Its just no one can lay blocks and thats not a good enough reason to say its better.In NJ i only saw blocks for basements.Here theres few basements and most all foundations are 2 feet high.If you go 10 feet high you need some forms for that, A block mason would be done before the forms were up.
I don't know why so many here are pushing you towards ICFs when you want to build an unheated foundation under a porch.
And all this talk about poor soils causing foundation failure! If you backfill with gravel, and have good drainage both at the footings and at grade as proper building practice requires, this isn't an issue.
Either poured concrete or block will function just as well in holding up your porch. The most important difference will be in who's available in your area to do either option and what will they charge.
It's really as simple as that.
Solar & Super-Insulated Healthy Homes
Too many posters not reading the original post and then moving on through the others. Threads get sidetracked.
They can't get your Goat if you don't tell them where it is hidden.
another vote for ICF......
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
In the PNW, with a block wall, you will have a proscribed rebar schedule and you will have to pour all the cores, whether you drystack or not, all due to seismic construction requirements.
I, personally, prefer a poured stemwall because, regardless of what a couple other posters have claimed, a poured wall is stronger (you will probably be required to use a 3500# mix), although, from my impression of what you're doing, either is probably suitable.
I've done both block and poured foundations and find pluses and minuses to each.
If you're doing it yourself and are inexperienced, I suppose the dry stack would be the easiest as long as your footing is pretty flat and level. If you're matching up to an existing foundation and are drystacking, account for the nominal height of each block course (block are made 1/2" under callout size in all direction to account for mortar joints and mudsill width.
regardless of what a couple other posters have claimed, a poured wall is stronger
How strong do you want it? In "Masonry Design and Detailing: For Architects, Engineers, and Contractors," Christine Beall wrote:
Reinforced masonry structures designed in compliance with modern code requirements have successfully withstood substantial seismic forces, and the rigidity inherent in the masonry systems often reduces or eliminates secondary damage. Reinforced masonry buildings as tall as 10 stories survived near the epicenter of the 7.1 Loma Prieta, California, earthquake in 1989 and the Northridge,California, earthquake in 1994 without structural damage, glass breakage, pipe separations, or even cracking in the drywall or door jambs...
The only masonry buildings to sustain significant damage were older unreinforced masonry structures built before modern building code requirements and unretrofitted to meet stricter performance criteria. (p. 409)
I'm not sure how you came to the conclusion that a "poured wall is stronger." All three systems--standard poured wall, CFI wall, and reinforced block wall--have more than enough compressive strength for any residential foundation. That's because all three systems are made from concrete.
Poorly built, unreinforced block walls have not performed well when subjected to lateral loads. If they're properly detailed and reinforced, they are accepted in seismic areas by the IRC. The reinforcement requirements for masonry walls and poured walls, in fact, are joined in the same tables.
Notchman
Why refuse to accept that ICF's are already approved and meet codes? Plus they are really easy to do as a DIY.
If you don't need the insulational value there is still the savings of being able to DIY
Where did I refuse to accept ICF's?
I'm a certified for AARX ICF's and (I just looked at my files) I've put up 11 semi loads of them so far, all for new home construction, mostly highwall applications.
But the OP, as I understand, is doing a simple stemwall foundation (unconditrioned) to support an addition.
ICF's in this application would hardly be worth the delivery cost of a small order and more labor intensive and expensive waterproofing.
Notchman,
OK sorry!
However I still say that ICF's are an easy affordable way for a DIY guy to do this task without the expense of forms or hassles of block. If it's not going to be living space why worry about water proofing?
Well, mostly because you don't want moisture in a crawlspace so you direct it, instead to the perimeter drains. (Moisture that comes from water sprinklers, rain, snow, etc).
Waterproofing block or poured walls is pretty simple and, relative to waterproofing ICF's, faster and less expensive.
Notchman,
I made the assumption that the foundation already is water proofed. You assumed that the foundation isn't. Since water entry into the basement wasn't mentioned I believe there is credence for my position however your position is well understood.
If you had been here 6 1/2 years ago you would have been privy to the results of my waterproofing efforts on ICF's. I bought the waterproofing materials from my supplier who said I could apply it with a paint roller.. I did, however I am the worlds sloppiest painter and I wound up with that Goo in my hair as a result of my waterproofing.. someone here told me to spray WD40 in my hair to get it out and it worked like a champ. <grin>
Next time I wear a hat!
Very interesting discussion! For a diy small addition, one person I know used this system http://www.azarblock.com/ . There is also another similiar system http://www.haenerblock.com/ . I don't have a clue about availability in your area, but you could check for distributors on their respective sites.