House Foundation Formwork
House Foundation Formwork
(OP)
Looking at putting in my own foundation for a new house. The basement I'm planning is to have 10' high walls. Any suggestions for the best/easiest way at forming this? I'm currently considering using 10' lengths of plywood with 2x lumber for bracing with tie-backs.





RE: House Foundation Formwork
You definitely need a registered engineer based on you description.
RE: House Foundation Formwork
Mike McCann
McCann Engineering
RE: House Foundation Formwork
Not sure why you want to do this type of work. It is not usually that expensive and it is hard labor as well. You would be better off working on the high value items.
All the money in the house is in the finishing work, not the rough building. For example, a 2 X 4 - 8' long costs about $2. Trim boards cost $1-2/ foot. A kitchen faucet or a whirlpool faucet goes for $200-400.
RE: House Foundation Formwork
RE: House Foundation Formwork
I did start reconsidering the 10' concrete wall and may go with an 8' concrete wall with a 'knee wall' on top to give the basement more headroom.
I tried doing some searches for form rentals in my area (MA) but couldn't find anything so far. I do work with some structural engineers and they would make sure my formwork detail is fully braced if I go with building them myself out of plywood.
I have received some prices from contractors to do the work and was getting low to mid 20's for a 55x40 house, this is not a square house though just the overall dimensions. I figure I can do it for about 10k less.
RE: House Foundation Formwork
Other equipment needed would be vibrators, layout equipment, and a strong back.
RE: House Foundation Formwork
RE: House Foundation Formwork
RE: House Foundation Formwork
RE: House Foundation Formwork
Save yourself the headache, call an engineer to began with.
And homeowners wonder why their basements leak?
RE: House Foundation Formwork
RE: House Foundation Formwork
They are very Do It Yourself friendly. Some are better than others for a tall wall. I was an owner/operator of a concrete pump, and I pumped into about 10 different brands of forms. You will have to pay for quality. Nudura forms are some of the best. Superforms are good too. Most all of them will supply you with a video to show you how it's done. Some of the larger distributors will also have the bracing/integrated scaffold to rent to you. There is a great deal of information available on the 'net.
Good luck
RE: House Foundation Formwork
Constuction of the wall should be done in bits as not to have bustings and pressure build-up normally associated with long tall walls casted at a go. Casts in lifts of 1m(about 3ft) on spans of 3m (about 10ft) shoud be ok!. Rent the forms. It is better you carry out the job yourself as to have a feel of it(as long as you are an engineer!). You already have enough professional advices to see you through.
Good luck
Teddy
RE: House Foundation Formwork
What pressure are you referring to? Soil pressure is linear and proportional to height as is water pressure. Concrete hydraulic form pressure can be lessened by waiting for the early set of the cement, thus the slow vertical pace recommended, but it is still proportional to height.
RE: House Foundation Formwork
I do not know if I got your question as such if I answered your question well. If not, write again and please be clearer
Teddy
RE: House Foundation Formwork
RE: House Foundation Formwork
Tim
RE: House Foundation Formwork
For the hydraulic pressure I have little concerns. My soils are sand and gravel. When doing the test holes/perc tests for the septic we went down 10' in 3 different location on my land and no ground water. The BOH said not to bother actually doing the perc since any water would drain straight through the soil and would be very hard to perform. Just for caution I will still install a drain pipe on the inside of the footing with a sump pump as I have nowhere to drain to on my land.
RE: House Foundation Formwork
Good luck to all of us in our endeavours.
Teddy
RE: House Foundation Formwork
With a jig or mass production approach, you could make your panels en mass one day set them the next and work to prepare them thereafter. However, by yourself this will be nearly impossible. Most stick built systems can be panleized around 4x8 sheets of Plyform - plyform is not simply plywood. It has subtle differences in production not limited to preapplication of form release agent that make it different that what you will find at your home improvement center.
For the heights you are taking about with that square footage, stick built walls would likely be the approach we would use. That said, we would have some means of hoisting you wont like have and our crews are led by foremen with years of experience. We can beat the linear footages listed above but I don't think you can.
If you had one run of wall to complete, without corners and other details that really benefit from experience, I would be more encouraging.
At the height you are working with, prescriptive tie layouts would be adequate and industry norms would not likely require an engineered drawing for such situations.
I design and oversee formwork and shoring operations for a living. If I were in a similar situation, I would round up a favorable supervisor and crew and pay them for a weekend of work. I would work happily amoung them, but I would not expect myself to handle it.
If you are having trouble finding contractors in your area, try contacting your local commercial construction supply or contacting form tie manufacturers and see who sell their products and who uses their products in the area. Several manufacturers are Dayton Superior, Meadow Burke and Gates amoung many others.
Formwork is far from an exact science, but requires a skill to do it well and not waste money. With your scope of work, the blowout you were warned earlier of could very well cost you as much as the form rental when you account for cleanup, lost materials and time to reset and prepare to pour again.
Best of luck,
Daniel Toon
RE: House Foundation Formwork
DO NOT try to form and place your own concrete foundation. I will almost gaurantee it will end in failure and cost you a lot more then hiring a knowledgable contractor to do it in the first place. There are so many things that can go wrong and result in failure I hesitate to even start. Watching someone perform there job is not real world training. The reason it may look easy is because they have had their share of catastrophies and learned from them. Stay at work, do what you know, and let the contractor do their job.