Foundation costs

[hhbartlett]

I'm back to the drawing board for my place. Money is an issue, so I'm looking for some feedback on a point of confusion.

What is the least expensive type of foundation to put in, all things considered?

I was considering a poured cement or block (again, not sure what is the cheaper route) frost wall. But, ideally I'd want insulation around it, and then I'd have to build a floor system with joists, centre beam and sheathing.

I also considered a frost protected cement slab. That means 12" footer around the perimeter and possibly down the middle, and 6" everywhere else. Not as cheap as I thought once all the rebar, steel mesh, foam underlay etc. is counted. However, no floor joists or sheathing needed, and we can just finish the cement instead of putting in flooring.

I'm looking at sonotubes and cement piers as another option. Certainly I can do pretty much all of that myself, saving labour costs, and material won't be as much as a frost wall. However,  I'd need to add some kind of skirting and insulation to avoid freezing pipes and what not, so that has to be considered too.

If it matters, I'm in Canada, 48" frost level (not northern Canada) and probably planning around 24' x 36'. My space is pretty level, I'm building where an old house burned down a few years ago, it has since been filled in, and drains well.

So, does anyone have an opinion on the cheapest foundation system, and by how much?

[Squirl]

How do you plan to excavate?


I did concrete block.  By the time I added in the extra labor and gas, I should have done poured concrete.  If you can protect the lumber on the forms to reuse for the build, the cost and time savings makes poured about the same cost of block, maybe just a little less.  If you are filling the blocks with concrete and rebar, the forms and poured concrete are competative, with reused lumber cheaper.

FPSF are good for many.  I believe the minimum depth anywhere is 16".  You can usually rent a small trencher or mini excavator to get the depth which saves some money. The rigid foam is usually a killer depending upon location.  Some locations may require a wing of insulation, which raises excavation on insulation cost considerably.  Most people pour a slab, which requires more labor (hard to do alone).  I also didn't opt for the slab because I wanted the possibility of changing things over time.

I didn't go with FPSF, because they are only code approved for buildings heated year round with a mean temperature above 64 degrees.  They work by forcing the heat dissipated through the floor of the house under the footing for the house to keep the soil beneath the footing from freezing and heaving the foundation.  I wanted the option to leave my place unheated over the winter in case I become a snowbird someday.
http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_4_sec003_par020.htm


If you have good soil drainage, there are also permanent wood foundations, which save a ton of labor and are very fast.  They last well in northern climates.  They cost a bit more though, and if cost is an issue they might not work for you.

[MountainDon]

For the size of structure you're looking at and the climate, forget about pier and beam. That's my opinion based on typical building codes (which do not support them) and things I have learned in the past year or so from conversations with engineers and other knowledgeable people. Plus a few real life observations of pier and beam problems others have experienced.

What would I use / recommend as the least expensive good foundation? I'm not certain. There are many variables that could be quite different from one locale to another. Cost of excavating, cost of concrete especially when there are distances and reddi-mix trucks involved.

[hhbartlett]

How do you plan to excavate?


I did concrete block.  By the time I added in the extra labor and gas, I should have done poured concrete.  If you can protect the lumber on the forms to reuse for the build, the cost and time savings makes poured about the same cost of block, maybe just a little less.  If you are filling the blocks with concrete and rebar, the forms and poured concrete are competative, with reused lumber cheaper.

FPSF are good for many.  I believe the minimum depth anywhere is 16".  You can usually rent a small trencher or mini excavator to get the depth which saves some money. The rigid foam is usually a killer depending upon location.  Some locations may require a wing of insulation, which raises excavation on insulation cost considerably.  Most people pour a slab, which requires more labor (hard to do alone).  I also didn't opt for the slab because I wanted the possibility of changing things over time.

I didn't go with FPSF, because they are only code approved for buildings heated year round with a mean temperature above 64 degrees.  They work by forcing the heat dissipated through the floor of the house under the footing for the house to keep the soil beneath the footing from freezing and heaving the foundation.  I wanted the option to leave my place unheated over the winter in case I become a snowbird someday.
http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_4_sec003_par020.htm


If you have good soil drainage, there are also permanent wood foundations, which save a ton of labor and are very fast.  They last well in northern climates.  They cost a bit more though, and if cost is an issue they might not work for you.

Most people around here use poured concrete, so I'm guessing there's a reason. I'm going to probably concede that work to the concrete guys; I know they are far better at it than I am where I have zero experience with concrete anything. They provide their own reusable forms usually. There shouldn't be any issue with getting a truck to the site. Looking at FPSF, I would need wings where I am, I think 2 feet maybe. What I don't like about the slab is there's no easy access underneath later on in case of problems or changes. I guess there's pros and cons to either. So, here's the issue; is it cheaper to do frost wall and standard floor, or pour an FPSF.

[Squirl]

I didn't even consider a pier foundation for that size house. 

I just read your other post about your family not having a place to stay if it is not built by winter.  When factoring other costs such as rent or mortgage payments, time is money too.  Say if block costs $500 less than poured concrete and it takes an extra month and you have a month extra of rent or mortgage payments, the savings end up actually costing you more.  I would factor in time and labor as costs too.

[hhbartlett]

For the size of structure you're looking at and the climate, forget about pier and beam. That's my opinion based on typical building codes (which do not support them) and things I have learned in the past year or so from conversations with engineers and other knowledgeable people. Plus a few real life observations of pier and beam problems others have experienced.

What would I use / recommend as the least expensive good foundation? I'm not certain. There are many variables that could be quite different from one locale to another. Cost of excavating, cost of concrete especially when there are distances and reddi-mix trucks involved.

Good to know about the piers MountanDon. I wondered about that. However, there is a newer thing around here called Postech which is a variation that looks interesting, and is allowed by code:
http://www.postech-foundations.com/

I don't know the cost yet, but it's a possibility as well.

[hhbartlett]

I didn't even consider a pier foundation for that size house. 

I just read your other post about your family not having a place to stay if it is not built by winter.  When factoring other costs such as rent or mortgage payments, time is money too.  Say if block costs $500 less than poured concrete and it takes an extra month and you have a month extra of rent or mortgage payments, the savings end up actually costing you more.  I would factor in time and labor as costs too.

Well, we will probably not be building this year at this point. It would be too rushed and panicked by the time we'd get to be there, I need more time for planning, and I need a better handle on my budget. I won't put my family through that stress, instead we can have some fun getting ready there this year (camper is already there, along with well, septic, etc. - I just need to hook it all up). Plus, there's a nice old barn on the property that needs some fixing (barn was built by my great-great-great-grandfather and his father when the family moved to the homestead).

[MountainDon]

.... there is a newer thing around here called Postech which is a variation that looks interesting, and is allowed by code:
http://www.postech-foundations.com/

That is a totally different thing! Those have an engineer involved. They are used in many places where other foundations have failed. Each case is assessed on its own.

[hhbartlett]

That is a totally different thing! Those have an engineer involved. They are used in many places where other foundations have failed. Each case is assessed on its own.

They look pretty cool. Pretty slick system, they come in and install in one day, no excavation, no mess, no disturbing the site. And they're guaranteed. I'm thinking it would save me a whole bunch of headaches.  I don't know what the cost of these are, but it's definitely an option.

[Squirl]

Are you doing it yourself or hiring it out?  I cannot attest to differences in contracted prices.

[old_guy]

You said "I'm building where an old house burned down a few years ago, it has since been filled in, and drains well. "

I am beyond my experience here, but I would be concerned that the fill would provide even less lateral support than the average installation for piers.

How deep was the original foundation?  Wouldn't you need to go past that fill to the undisturbed soil for the new foundation, even if it has been filled for a few years?

[UK4X4]

I can help with piles.......but not the rear end type !

I got quoted recently for 12 off piles  20ft deep to fully support a 26 x 36 2 story

costs were between 12K and 17K depending on supplier and type.

The highest was for square floopy ones and the cheapest was the ones I prefered 2 7/8" diameter round ones.

there are many suppliers of helical piles- its not the cheapest solution by far - but for my mountain top soils they seem to be the best bet.

Just having the grade beams designed up now....hopefully submit plans and start this summer, but with the high costs.....I'll be close to 25K by the time I have just the foundation done as need to add some more piles to the porch and the grade beam will be pretty huge to keeps things ridgid

if your on a flat non moving area with simple frost heave then I think poured will be your best bet, I'm doing crawl space for the additions and changes that always occur

Likewise on the above in regards to the back filled space- you'll either have to pull it out and mechanicly pack in proper fill -or get the foundation down to firm un disturbed original soil

[UK4X4]

■Produced from galvanized steel, therefore immune to corrosion !


from Postech website......sorry not imune just takes longer but will happen !

[hhbartlett]

You said "I'm building where an old house burned down a few years ago, it has since been filled in, and drains well. "

I am beyond my experience here, but I would be concerned that the fill would provide even less lateral support than the average installation for piers.

How deep was the original foundation?  Wouldn't you need to go past that fill to the undisturbed soil for the new foundation, even if it has been filled for a few years?

You raise some interesting concerns. This is exactly why I'm not plunging ahead right away.

The old house burned down 7 years ago. Looks like the fill was mostly gravel. However, I am unsure just how much was removed, or if there's remnants of the old foundation still there, or what. I don't know how deep it was, but I'm guessing 8' as they used to have a big old sawdust furnace down there at one point. However, there is part of it that there was no foundation  to speak of. The old house was built early 1800's, then added on to in 1880's, 1930's, 1950's and 1970's (it ended up being 90 feet long). Unfortunately most of the people that knew anything about it are now dead.

I guess I'm going to have to have a chat with some foundation and cement guys from the area.

[hhbartlett]

Are you doing it yourself or hiring it out?  I cannot attest to differences in contracted prices.

If I can do it myself, I will, but for cement stuff of any size I'm probably going to let people that know what they're doing have at it. The foundation, anyway. The rest of the house will be all me.

[hhbartlett]

I can help with piles.......but not the rear end type !

I got quoted recently for 12 off piles  20ft deep to fully support a 26 x 36 2 story

costs were between 12K and 17K depending on supplier and type.

The highest was for square floopy ones and the cheapest was the ones I prefered 2 7/8" diameter round ones.

there are many suppliers of helical piles- its not the cheapest solution by far - but for my mountain top soils they seem to be the best bet.

Just having the grade beams designed up now....hopefully submit plans and start this summer, but with the high costs.....I'll be close to 25K by the time I have just the foundation done as need to add some more piles to the porch and the grade beam will be pretty huge to keeps things ridgid

if your on a flat non moving area with simple frost heave then I think poured will be your best bet, I'm doing crawl space for the additions and changes that always occur

Likewise on the above in regards to the back filled space- you'll either have to pull it out and mechanicly pack in proper fill -or get the foundation down to firm un disturbed original soil

Good info to know, thanks. 20 feet seems pretty deep! I can see I'm going to have to get some local experts to have a look at what I've got. If I have to pull it all out anyway, might as well pour a full basement. Which will be $30k. 

[Squirl]

Great point on the fill, I didn't even pick up on that.  With normal pier foundation you would be distributing the weight of the house on a much smaller square footage of land than a full footing let alone the lateral support issue.  I would never do that on fill.

Will you do the excavation?

If you do the trench wide enough a quickwall drystack block system might be for you.  Speedfunk did an excellent job on his.  The important thing is to spend a lot of time on setup and finding your corners with batter boards and plumbs.  Don't short cut that.  It costs a little more, but only a few hundred.  It doesn't require a large amount of skill, but decent patience.  It is good for the go it alone type, not a lot of experience type.  It would still save you a few thousand over probably hiring someone.

http://www.sakrete.com/products/detail.cfm/prod_alias/Surface-Bonding-Cement