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Does anyone know of a website that describes common techniques and specifications for basement construction? I am looking for info on drainage, waterproofing, backfill material, sump pumps etc..etc. Also any building codes that apply, such as min wall thickness, reinforcement requirements, etc.
I am drawing a floor plan for a builder and neither of us has built one before. (they’re not done very often around here) I will check the local building department but I like to know a what I am talking about before I go in 😉
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Some of the back issues of FHB covered some of these topics. Are there any reputable basement contractors around there? Where are you located?
Actually different regions have different ways of doing things.
John
*Thanks for the response,I am sure there are concrete contractors around here who know basements, but the guys we have worked with have not done them and are subing it out. (I live in Idaho) There are not many basements put in here. I would guess off the top of my head maybe 1 in 100 (maybe less) new const homes have a basement put in. I have a pretty good understanding of the process in general from info I picked up in magazines, but I was hoping for something more formal. I am sure I will get it figured out though...
*chester.. the decision tree is forked.. poured concrete or cement block....once you make that decision the rest can follow..that decision should be based on what teh locals do.. or what you are willing to do yourself..so.. form the walls.. or lay them up ?
*I'd recommend forming the walls if possible. Stronger in my opinion. If you do elect to lay them, grout the blocks full of concrete and make sure that you add rebar horizontally and vertically. Around here the aluminum wall forms are available for rental, but they could be built out of plywood. Actually ICF (insulated concrete forms) are an excellent option. Make sure you don't skimp on the waterproofing. A sprayed on membrane is the way to go. We subcontract our basements. We let the guys who do it everyday do the work. Just had a 2000 sf basement poured last week. Good luck,John
*I guess to answer your original questions.-a minimum 16" X 8" concrete footing with rebar.-4" perimeter drain inside and outside the footing leading to a sump pit and/or a gravity drain if possible.-8" X 9' tall concrete walls (steel reinforced). 9' walls allows for headroom once mechanicals are installed and necessary beams are installed.-sprayed rubberized membrane on the exterior of the wall for waterproofing covered by a foam board (can't remember proper name) for a drainage plane and to protect sprayed membrane on backfill.-minimum 12" of gravel over the top of perimeter tile on outside.I don't think I forgot anything. And like I said, some back issues of FHB covered some of this.Good luck,John
*http://www.tuff-n-dri.com/ and keep the tile inextto the footing.
*Chester,Draw your plan per Johns recommendations. Call your local architect, tell him/her your looking for someone to review your plan. This will keep your cost low. Maybe $200.-$300. Also, it may be in your best interest to have the soil bearing pressure verified. Architect / Engineer can recommend someone for testing. Don't wing this. Mistakes can be very costly.I spent some time in Idaho myself. Mountain Home Air Force Base. 89 thru 92. I have'nt been back since.Good Luck-
*Thanks for the info, guys.D- Does "I have'nt been back since" mean "and I wouldn't go back if you paid me"? I guess there are people who like southern Idaho, but I don't care for it too much. I hate desert and sagebrush. I grew up in New Hampshire so I miss the trees. As I write this I am trying to figure out why I am still here...
*Chester,I spent some time in Twin Falls. I had a blast there. Even better was up in Stanley, the sawtooths. Unreal country.I'll give you some advice about basements. Be very careful about the levels, the relationship in height between your footings, the height of the garage floor, and the house itself. If you don't plan all this out, you may end up with some strange elevations. The house can look like it is sticking up out of the ground, or sunk in, and you may end up with several steps in the garage, to put all this to the extreme. You can also lose headroom in your basement (or gain it). Consider the lay of the lot, where the high and low points are and how the house should end up.If it were my house, I'd pay marginally more, and pour 9 foot basement walls. It's great not to worry about heat runs, the extra headroom pays huge dividends if you use the basement for a shop or rec room.I just did a house where I dug the hole, poured the footings, set ICF forms, and poured the walls. These were all firsts for me on such a large scale. With some research, attention to detail, and hard work, I pulled it off. It's not that mystifying. But small mistakes down there can magnify to the rest of the house if you get screwed up on level or square. Get some good lasers...MD
*I used a foundation wrap this past year. It was very similar to what's shown here. http://www.deltams.com/deltams/index.htmlI really liked it, and will never build another house that doesn't have this stuff on it. Definitely pay attention to drainage and waterproofing. It's a lot easier to do right the first time than to fix later. BTW - Why is it that there are so few basements in that area ?
*Rod - I don't know why they are so uncommon. Maybe since framing labor is so cheap here relative to other parts of the country, it is more cost effective. (Although I would guess that concrete labor would be lower too) Also, it seems like some areas have to put their footings deeper underground than we do. (We use 24" stemwalls on 8" ftr.) If you have to go down further anyway you would have less cost to complete it as a basement.Mad Dog - Yeah, Stanley is amazing. The mountain lakes around here are great too. Someday I want to take a charter flight over the Sawtooth Mts. I bet it's worth the money...
*chester, i'm your neighbor to the north, in the Montana sagebrushy desert. I built an all-weather wood foundation with french drains, waterproofed with the plastic dimple membrane Ron mentioned above. (Ron, i'm glad to know that solved your problem!) I've had no leakage whatsoever and there are lots of advantages to this method over concrete or ICF's.Here is a great link on drainage, very important, especially with clayey soils:http://www.jlconline.com/jlc/archive/foundations/foundation_drainage/index.htmlAnother on wood foundations:http://www.wolmanizedwood.com/permanent.htmlBe sure to put down plastic sheet under the slab and insulate with foam board--the foam is expensive, but it makes a huge comfort difference.
*Splinter, the all-weather foundation is an interesting concept. I had never heard of it until the other day as I was hunting for basement info I came across a webpage on it. My gut response was that it was the nuttiest thing I ever heard of, but looking into it further it appears to be a very reasonable approach. It sounds like you are satisfied with it. What made you try it? Do others do it in your area?Why did you decide to put in a basement rather than build above ground? Rod's question has me wondering why people don't put in basemnts here. (or why they do put them in other areas)
*Chester, some of the reasons i went with wood over concrete are particular to my case, but here goes:I'm short and female, did the work alone except for a bit of help from my 70-something Mom. All the wood parts were maneuverable for me--nothing heavier than a sheet of treated 5/8 ply. I made up 8'x8' panels, sheathed horizontally on the bottom only. I screwed framework and sheathing together with 3" and 1 1/4" decking screws, staged where they were to be stood up. The only help i needed was maybe a half-day from two strong friends to stand them up while i shot the bottom plates to the footer with a ramset. It took me about a week, not including snapping lines or mortaring the block stem wall on the daylight side of the basement where i didn't have french drain or dimple fabric.The costs for wood and cement were within a couple hundred dollars, but i didn't have the additional cost to rent forms or the cost of a crew to pour. I used treated 2x6x16's for my footer forms, them cut them into 96" lengths for the studs. I have sandy soil, so i used a standard 8x16 footer with (2) #5 bar, though if you have stable soil, they recommend compacted gravel and a 2x10 for a footer (or used to). I wouldn't trust a 2x10 not to split, however, so would use a concrete footing for that reason and because it's easier to get it dead level. (I bought a laser level for this job--worth its weight in gold.) If the footer is level and the panels are square, the foundation practically puts itself up. Use the cap plate and offset the top band of sheathing to tie the panels together. I measured diagonals even before bracing and i was out only 1/4"--pretty amazing!I'm a woodworker, so i already had all the tools to do the job, like a 12" miter saw and a few cordless drills. The ramset was about 35 bucks, i think, plus a hundred charges or so for it. I used yellow, i think, one per bay, 16" O.C.I could more easily change the window and door openings if i wanted.I like that i already have bays for insulation (icynene bec. below ground) without having to fur the walls out and lose more floor space, that i have a nailing surface for the drywall, and that the dimple fabric was easier to attach to the exterior with 3/8 ply over the selvedge than the way the manufacturers show with plugs nailed into the concrete.I was rolling a house on to it, so i could get a little movement in the wood walls to match to the rim joist precisely when setting the house.Others in my area are using it more. The thing is, when done, it looks no different than a concrete foundation--well, except there aren't blowouts or wobbles! ICF's are gaining greatly in popularity for foundations, but so is Tyvek, another product i think is more hat than ranch. The ICF's were more than the cost of the concrete or wood foundation, and that was before buying the cans of foam to put them together or the concrete to fill them. I also didn't like what i read about foam drawing termites--they're jsut starting to be noticed in Montana--but then the copper solution is probably not good either...tough call on the environmental/health factor, so i went with money, and the ease of installing electrical and plumbing in the wood stud bays.One lesson learned: in retrospect, this makes me sound pretty dumb, but don't attempt to backfill one leetle bit before setting the floor joists. :(Why a basement: i like two floors for compact utils, efficient heating, not to mention the stair exercise, so having the lower one in the ground acts like a flywheel for temp. I've become dedicated to the walk-out basement plan with my woodshop on the bottom floor--it's naturally 20 degrees cooler than walking outside in the summer. When i leave, it is easy to make a couple more bedrooms and garage down there for resale if you plan for egress and frame for a garage door. I put EPDM on a deck on the downstream side where the garage door is--ready-made carport and/or dry outdoor work space where i can spray lacquer. As i recall, a sloped site makes for good feng shui!Everyone i know in southern Idaho has a basement, so i've been puzzling why they aren't where you are...? Crawl space is 36" here so one might as well go the distance as long as you have the backhoe on site. You might also want to explore the idea of a bermed basement, where the excavated dirt is pile against the wall above grade.
*Hey Splinter - I have a partial roll of the stuff left over, if you're interested. It's 8' 3" tall. I'm not sure how long it is. I think it started off as a 50' roll, and I used about 15 or 20' of it. I'd make you a heck of a deal if you think you'd use it. Thanks again for suggesting the stuff. I owe ya a big smooch or something if we both make it to a fest one of these days..........(-:
*What, Ron, you can't use it? You're getting out of the spec house business??? I don't have the next place picked out yet, so don't know what height roll it will require, but thanks for the offer. You know, i once thought of becoming a rep for those guys, i was so impressed with the product. A heck of an opportunity for someone...
*Splinter, thanks for detailed description. For my next house I will look into it. (This one is just a floor plan for a builder, and I will mention it to him but I doubt he will want do anything unconventional)Couple more questions... Does it smell funny? Either from the treated lumber or dampness?How did you finish the foundation between the grade line and the siding?Do you build your houses completely by yourself? If so, I can relate. I do a lot on mine, but I have subbed out the mechanical stuff, foundation, and drywall. The framing in particular is probably not very efficient to do by myself. I would probably be better off hiring it out and doing something else, but it's fun.
*i Does it smell funny? Either from the treated lumber or dampness?Dampness and smell was completely gone in no time in summer, along with smell, but i used a good mask when cutting the PTL. The major fear i had of warped material didn't occur as delivery to erection was a short time. i How did you finish the foundation between the grade line and the siding?On the concrete foundation, i used dimple fabric to grade, fixed with term bar (keeps dirt from falling in and plugging up the air space). Then i parged the raw foundation wall with mortar above grade for looks.On the wood foundation, i used dimple fabric to grade, then lapped 3/8 ply (same thickness as dimple fabric) over the flat selvedge and ran it up and over the seam with the house rim joinst, so i could tie the two parts together well. Over that, i nailed Hardi-Panel (i got a deal on some at $18/sheet) so it extends just below grade. Over this, i have decks/catwalks all around with EPDM covering acting as flashing extending up under the siding, which is Hardi-Plank. If i hadn't built the decks, i would have flashed the HP with some sort of Z-metal over it and under the siding.One of the things i forgot to mention is that i used some old paneling as a slip sheet to protect the dimple fabric while backfilling. Otherwise the compaction catches on the texture and stretches the sheet down. i Do you build your houses completely by yourself?Not on a single house, but on various remodels i've learned to dig septic systems to running ridge cap. To my mind, the mechanicals are the most fun, and my jurisdiction allows me to do them on my own home. If yours does, and you have the time to learn, Taunton has some comprehensive, clear, up-to-date books on these areas as well as this website.
*Are you in a seismically active area? That should be another 'basement' consideration if you are.
*No need for basements in Calif, because 1. The ground doesn't freeze. 2. Earthquakes.