I volunteer with Habitat for Humanity. We basically build the same house & in the past, have always built our crawl space walls with block. We’re debating the pro’s & con’s of building our own forms and pouring the walls (approximately 5-6 course high). Our premises for considering pouring are that we: 1)would gain time and, 2) be less susceptible to water leakage. Would like some feedback on:
1) your pro’s & con’s with poured walls
2) techniques (best practices) to observe when preparing and/or pouring walls, and
3) publications, references, etc. on building forms, reinforcement, release compounds, etc.
Thanks in advance,
Rookie
Replies
Most all poured foundation walls today are built using manufactured forms that are reusable. At the current ridiculous cost of plywood, I wouldn't even consider the project, if I were you, done the way I think you inquired. With all your free labor, however, consider instead the use of one of the many available foam block products that go together, then are reinforced and braced, and filled with concrete, to make walls. Start at Polysteel's website, and keep surfing.
crete work is hard on forms so many of the larger companies cycle their older forms out of service every so often. They are still useable and are sold used but it is possible that you could wrangle adonation or discounted price. storage and transportation of the forms is another storey.
Excellence is its own reward!
try an ICF system (insulated concrete forms). there are several systems out there ( Diamond Snap, Eco-Block) and the manufacturer usually provides an excessively detailed instruction manual with the system. Be sure to get the right system for a short wall such as a crawlspace. Don't get roped into buying a heavy duty system designed for basement walls when you don't need it. Have fun!
mgueriera
i've worked on a habitat house here and we used the icf's[foam blocks].basiclly they are easy to work with but if you had a couple of guys that could be at every house to help guide the volunteers it would really help.we did a full basement plus 8' walls with them and it was pretty much the blind leading the blind for the first couple days.good luck
I wanted an underground concrete house. At the time there were few concrete wall contractors here and the prices were prohibitive. Two booklets, Cast-in-Place Walls from the American Concrete Institute (ACI) and, more importantly, Construction Manual: Concrete & Formwork from the Craftsman Book Company in Carlsbad, CA, got me going. The guys helping knew even less than I did as I'd read the books.
Haven't priced CDX plywood lately but that's what we use, with snap ties and wedges. This is old-fashioned slow(er) forming. Cheap materials (except for maybe the plywood now) and you can do anything. I was told the CDX wouldn't hold up for the whole house but that was wrong. I figure 8-10 pours minimum. That's using used motor oil on them for form release. They live year-round outside unprotected.
I quit using strongbacks and only use single walers with blocks, minimizing the required 2x4's. Initially I feared an 8' wall so we poured this place in 4 lifts of 4'. Wouldn't do that again, but if you only want a crawlspace it's the ticket.
You're correct about concrete advantages, plus it's immensely stronger. Only problem is if you decide to remodel. Don't forget the vibrator. We nail 2x4's to the footing to hold the plywood bottoms in place. Cut nails work if you're wanting Popeye arms, otherwise powder actuated is great.
Half the battle is making sure you can place the concrete via chutes. We've done a lot of pouring out of loader buckets. The trade associations think insulated forms, that you leave in place, are the answer. For you, they might be. I'll stick with my plywood.
Good luck.
PAHS Designer/Builder- Bury it!
If your plan to switch to concrete doesn't pan out, you should consider improving your waterproofing system. Quality systems can be installed easily by people with minimal skills. It would be easier to teach better waterproofing to novices than forming concrete stemwalls.
carpenter in transition