Replies

1. 
   rickwainman | Dec 14, 2002 02:57am | #1

   Hey, DFORD0 (what does THAT stand for? drive no Fords?)

   Anyway, I just got through doing exactly what you said. I liked the stuff, just a few thoughts:

   Since I was doing it myself, I filled every core. Not that much extra dough, plus I needed the strength for the downhill side.

   I used about a million brick shims for keeping the stack level and true.

   Don't forget to keep the wall damp where you are working, otherwise the compound dries too quickly.

   Don't forget to plan your footings to allow for extras such as bricks or interior insulation. In hindsight, I would have used 12-inch block on the bottom and then switched to 8-inch to create a brick ledge.

   I don't know what kind of footings you are anticipating, but I used rubble trench. Check out FHB book/articles.

   Even though the instructions say you can use the bond compound as a sealer, I still used asphalt over it below grade.

   Anyway, for someone such as myself with no experience laying block, it worked very well. Have fun!

1. 
   IronHelix | Dec 14, 2002 03:30pm | #3

   If you have stepped footings..remember 8x16 concrete blocks "ARE NOT" that size. Measure your blocks to determine the manufacturer's specs for calculating your masonry modular units and step lengths.

   Definitely vertical and horzontal rebar with bond block to tie it all together. Nice system for solo work or small applications. Horrid to keep level and plumb if the block mfg specs are random or mixed.

   Often consumes lots of extra time for adjustments and cuts........sometimes enough extra to have done it the bestway................poured concrete walls.

   IMHO................................Iron Helix

1. 
   Piffin | Dec 14, 2002 07:29pm | #6

   I think the recommendations for the system are to lay the first course in mortar. That gets it attached to the footer and helps start the leveling off on the right foot..

   Excellence is its own reward!

   "The first rule is to keep an untroubled spirit.

   The second is to look things in the face and know them for what they are."

   --Marcus Aurelius

2. 
   Piffin | Dec 14, 2002 05:54am | #2

   DO NOT

   I repeat, DO NOT use this method in clay soils. Go way beyond normal to make surre you have good drainage.

   And never build this method without filling the cores and rebar. I've seen dozens of failures caving in.

   For my money, The only block wall I would build on like this would be above grade.

   .

   Excellence is its own reward!

   "The first rule is to keep an untroubled spirit.

   The second is to look things in the face and know them for what they are."

   --Marcus Aurelius

1. 
   rjw | Dec 14, 2002 04:50pm | #4

   DO NOT I repeat, DO NOT use this method in clay soils. Go way beyond normal to make surre you have good drainage.

   Piffin, I'm wondering.  Block and bond ("BnB") is supposed to have much more strength against lateral forces than standard block laid in mortar, and he's talking crawlspce, not basement.

   I haven't seen BnB in over 20 years, and have never seen it other than in passing, so I don't have any actual experience, but I'm wondering if you were thinking more in terms of a basemenbt than a crawl space.________________________________________________

   "I may have said the same thing before... But my explanation, I am sure, will always be different."  Oscar Wilde

1. 
   Piffin | Dec 14, 2002 07:26pm | #5

   If you were here right now, I could show you four crawlspace foundations built this way that are in various stages of failure from the combination of groundwater, clay, and this system.

   Similar jobs in similar soils here do OK if ladder wythe and poured, re-inforced cores every four feet is the foundation.

   Block laid with just mortar is about as equaly prone to failure, IMO. The Stack'n'Bond does help keep the moisture from penetrating the block itself and probably the interior.

   The fact you haven't seen one done in a long time tells a lot, don't you think? There's a reason it fell out of favor.

   As to comparing test results of strength, I would suggest that you are not really comparing apples to apples for actuall installations. The reason is that the stack'n'bond is more likely to be used by a DIY with less experience and understanding of necessary precaustions, while the running bond mortar laid block is more likely to be laid by an experienced professional. On the whole, that would tend to lead to a mean result for SnB of lower quality than for a mortar-bonded wall system, though the current thread by dumas here may skew my conclusion.

   ;).

   Excellence is its own reward!

   "The first rule is to keep an untroubled spirit.

   The second is to look things in the face and know them for what they are."

   --Marcus Aurelius

1. 
   rjw | Dec 14, 2002 09:40pm | #7

   Thx, good points.

   Do you see any above grade installations?

   FWIW, the two projects I saw up close in the 1980s were a full basement and an above ground methane generator.

   One of the BnB specs was to use mortar every x number of courses (every 6?) to level things out.

   Those joints were where leaks occurred; it seemed like the fiberglass fibers in the parging material couldn't adequately span the mortar joint width.

   I don't remember the soil type for the full foundation, though.________________________________________________

   "I may have said the same thing before... But my explanation, I am sure, will always be different."  Oscar Wilde

1. 
   Piffin | Dec 14, 2002 10:21pm | #8

   When you say that's where it leaked, did you mean where it got into the wall or where it found it's way to the interior? If the latter, it may have been leaking further up and collecting on the mud spread gob on the inside of the joint, sitting long enough to wick through to the inside, maybe.

   Solving puzzles like this with practical application is so much more satisfying and productive than counting balls or arguing politickles.

   Excellence is its own reward!

   "The first rule is to keep an untroubled spirit.

   The second is to look things in the face and know them for what they are."

   --Marcus Aurelius

2. 
   Davo304 | Dec 15, 2002 03:01am | #9

    Here are my experiences concerning some of your questions/comments:

   "have you seen any above ground walls using B-Bond method?..."

   Before the now accepted practice of covering old brick buildings with synthetic stucco (Dryvit) we had several 3 story buildings "parged over with B-Bond. One entire city block worth of brick buildings had this procedure done 15 years ago. Has held up rather well except where some window openings were blocked off with plywood and parged overtop. You could not detect the blocked-off window opening for approx 3 years...after that the parging shrunk around the opening enough to "telegraph" a ghosting of the window 's position.  Openings that were instead filled in with block instead of plywood also now show a "telegraphing" but not nearly so bad as the plywood -only openings.

   I see B-bond in use quite a bit as a parge coat overtop of older fondation walls. Our lumber yards all still carry the stuff.

   Below grade, my fruit cellar wall was caving in. It was a block wall.  I removed much of the wall, installed new block, and used hydraulic bottle jacks and wood shoring to force wall back into original position, then B-bonded entire wall. After b-bonding, shoring braces were removed.  That was 12 years ago...this wall has never moved again.

   Father-in laws' above ground, one car garage ( built partly into the side of a hill) had one wall caving inward due to ground "push." Wall was jacked backed into position and coated with B-bond.  That was also 12 years ago...has also not had any movement problems since.

   My garage/workshop (36ft X 24 ft) was framed on top of a 2 course high B-bond wall. This wall was built on top of a highly re-inforced concrete slab. The soils underneath this slab is clay.

   "I think you embed the first course in mortar as a leveling course..."

   That is correct. Or, you can bond them using an approved construction adhesive. I went the adhesive route.

   "stable b-bond walls were those using ladder type wire wythe reinforcement between the courses and filling the block cavities every 4 ft...."

   This was the method I used...I have no cracks or shifting...very solid wall... now 7 years old. I actually filled more cavities than just those every 4 ft. The more fill you can add to a block wall, the better; I say.

   "had to use an awful lot of brick shims to keep rows level..." 

    I  must have been lucky cause I used very little shimming.

    Recommend you use corrugated brick ties as shim material. Blocks are not always true to size and shimming will be necessary. However, excessive shimming means your base ( starter course) was not leveled up too good to begin with. Footers must be as level as possible, or else care must be taken to level off first row of block, otherwise you will be fighting the job the whole way. Mortar is easiest way to level off the starter course if your foundation is off.

   "gaps in parging causing water infiltration..."

   Have not experienced this in the least. Parging looks as good as the day it was installed. No leaks or cracks.

   "Fibers in B-bond not covering gaps between blocks, causing failures and allowing water infiltration...."

   If you read the manufacturers instructions, B-Bond is really only intended to be used on block stacked tightly together. It is not reccommended for use on block walls that have mortar between them due to this very reason...fiberglass fibers are chopped too short and cannot adequately span the motar thickness between blocks to ensure tensile strength bonding. 

   The blocks in my wall were all stacked tightly together...experienced no problems. However, as previously stated, I have used this product to help reinforce traditional (mortared) block walls that were being pushed inward and also had great success; even though not recommended by manufacturer for this use. Have used this technique on repairing badly damaged concrete porches with block walls ( the walls were what I patched up , not the porch slab). All have met with great success.

   "tensile strength...."

   IMHO, a B-bonded wall, coated on both sides of the wall (not coated 1 side only), is much stronger than a conventionally mortar stacked wall. B-bond in no way diminishes compressive strength, since each block is sitting squarely on top of another block. The quality of the block materials itself would be the only determining factor in handling compressive strength...but not so with a mortared wall. The quality of the mortar directly affects this type of wall's compressive strength. If the mortar was a bad mix, it can crack under the wall's bearing (compressive) weight and these cracks will lead to water infiltration.

   Also, because B-bond covers the entire face on both sides of all block, the parging covers ( and clings to) a lot more block surface area than does a mortar joint job. Parging adds much greater tensile strength.

   Coal miners used this method for installing temporary shoring walls in mines, because they belived it could withstand both compressive and lateral forces much better than a conventional wall. I believe this practice is still being done today in some underground coal mines.

   Citing here from an article that was published in a FHB book titled "Surface bonded Block" by Paul Hanke....please note that the author points out that a lab test conducted by the USDA and the University of Georgia (years ago) found and concluded that a B-bonded type wall has an average tensile strength in the range of 300 to 500 psi. and quote "This is about equal to the strength of unreinforced concrete and is six times stronger than block laid up with ordinary mortar joints. Mortar has very little adhesive power, and virtually no tensile strength."

    

   "concrete block walls in general are not too good as foundation walls versus other types..."

   I tend to agree with this statement. For such a wall to remain sound, proper vertical and lateral rebar reinforcement should be used.  All too often, most block walls ( block wall basement construction is the norm in my area) are laid up without any reinforcement whatsoever. Core openings are seldom ever filled except for pouring in vermiculite as an insulator. Area masons/contractors tend to rely on the weight of the house or building to hold the block down in place, and they rely on the ground backfill pressure to keep the walls from buckling outward.  Subsequently, many a house has leaky , damp basements, which has generated  a whole new business avenue...those contractors who specialize in waterproofing basements.

   To safely deal with internal and external pressure loads, walls need to have extra  supports ( pilasters) built into them every so often. And B-bonded walls are no exception to this practice either. Accordingly, recommended practice is that above grade block walls should contain pilasters spaced at a distance equal to 18 times the thickness of the wall. If say you are building with 8 X8  blocks, then you should install a pilaster approx every 12 ft. along the length of your wall.  

   Pilasters were not needed in my 2 course high wall. They are needed more for bracing walls that are 6 ft.high or taller. 

   "b-bonding is waterproof..."

   Yes it is.

   I troweled it on approx. 3/16ths thick and then lightly sprinkled it with water for a few days afterward to allow it to properly cure....it is  after all a cementitious based  product. I have never painted it, just left it the natural grey color it is. It is 100% waterproof. Again, no problems with leaks or cracks .

   To learn more about the use of this product and other types of block walls, pick up a copy of FHB's FOUNDATIONS AND MASONRY. It's pretty informative.

   Merry Christmas.

   Davo

3. 
   joeh | Dec 15, 2002 05:40am | #10

   This is the URL of an old Dept of Agriculture publication on surface bonded block.  Pretty much all you need to know, but the Taunton book has better pictures. Joe H

   http://mha-net.org/msb/docs/surfbond.PDF

   Forgot these next guys, good pics here.

   http://www.thenaturalhome.com/drystackblock.htm

   
   

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   Edited 12/14/2002 9:53:53 PM ET by JoeH