My wife and I are in the planning stages of our house construction.  I am curious as to why PWF basement walls or not used or encouraged as much.  I have used the product before and the homeowners are satisfied with the turnout (after 6 years of being in the house).  It seems to be very cost effective and more efficient than concrete forms or blocks.

What we are thinking of PWF walls but with poured foundation floor (radiant in-floor heating).  If everything falls through it should be a 2000 +/- sq ft bungalow with an walkout basement.


What are you're thoughts or concerns ?

Thank you very much.

Where to start....PWF are not very "P" (permanent), they don't last. PWF's are not very strong, back-fill exerts a lot of pressure on a wall. But a PWF would go well with the fiberboard, OSB, track houses.

Wood should not be used in outside walls at all, let alone below grade.

I should of specified that the wood that is in contact to the elements and soil would be covered by a waterproofing membrane and then covered by a dimple product to protect the membrane while back-filling and to help with water. As for the pressure on the walls the interior partitions and floor joist that are installed according to code are not sufficient ?

I was also considering covering the PWF plywood that is exposed to the air with a cement board product that could be parged ?

Does this sound OK, what else should I consider.

I would love to use ICF but in my area and especially budget does not seem to be cost effective.

Thank you for the responses.

Cut back on cosmetic finishes or size of the house to build a better structure. Eliminate the basement. Build a smaller but better built house that can be added onto later.Build a house that can be made into a shop or office later. Something anything.

Can't you do a poured removable formed foundation?

bp,
You're right, it's seperated from the soil with the dimpled membrane, your drain tile/sump will take care of subsoil moisture, in theory it's isolated and it's sole purpose is to transfer house loads to the ground in an underground semi-exposed environment; the wood treatment is the insurance policy. You can easily insulate and finish the interior. It's designed to take backfill pressure, as they are approved in building codes and completely accepted by building officials; probably more so than SIPS in many areas.

Brad's first response is the typical mentality regarding PWF and you will probably see a reduction in value just for having one for the sole fact most people are generally stupid. Structurally they are fine. Brad's second response shows a complete lack of understanding of using PWF in the first place.

That said, my main concerns would be (subject to solid answers) 1.the amount of treated lumber in the living space and the associated chemicals involved and 2. insulating it properly with regard to mold (long term). My father in law had one put in in 2002 and they used fiberglass and poly to insulate. I saw it and thought "oh my god, a recipe for moldy disaster." It's a conditioned basement and once a year or so I peel open a section of wall in an unfinished portion and low and behold it's fine. His brother has a PWF unfinished interior pushing 20 years that looks no different from when it first went in. From my understanding there are alot of PWF in service that are aging well with no problems. Just beware if you want to sell you will scare alot of people off.

My next personal home will most likely have one (one less sub, more money in my pocket plus insulating benefits without big sq ft penalty) but if I were building a spec there would be absolute no chance in hell I would use a PWF.

"Structurally they are fine" for the minimum code. How will the dimple board be connected? I bet it will be by fasteners that puncture it and the membrane underneath. What is the oldest PWF you have seen? Twenty years is nothing, and you can only see the part visible from the inside. PWF is a bad idea.

We had a similar lengthy discussion about PWF foundations last year; with, as this year, lots of support for the product. My take as a buiilder is that houses shoulcl last hundreds of years and it makes no sense to use a product/system that relies on products with a limited lifetime (membranes, plastic, coatings) in a place where replacement is so expensive. Want to use cheap carpeting? fine; replace it in 5 years. A cheap foundation is the wrong place to save money. If you are going to live there the rest of your life, you are convinced you can keep it solid forthat long & you're not worried about resale or about what happens afterwards, go for it.

Ive been living with a PWF for 23 years, a passive solar two story with a finshed third floor being the daylight basemnt, never had a problem, there are three homes out of 35 on my street with them. This is not a regular street, homes are on two acre to 5 acre lots with a cost of 500K plus. All this and within a five minute drive to the west end of Kanata/Ottawa's high tech end!

The only downfall which has been stated is the resale, I will know more in a couple of years when I downsize!

John

I am very grateful for the responses. Every bit of information will help us. I was told by an architect that PWF basement had a theoretical life expectancy of over 75 years if properly installed and maintained over time.

The main reasons I was considering PWF was ease (time frame) of installation and then costs. I have seen a few SIPs companies promoting a PWF SIP but found them to be quite expensive. What would you recommend ? Would anybody be willing to post a approximate cost per sq ft for a certain product or technique ?


We have already downsized slightly in size but I still want the best bang for you're hard urned buck. Thank you!

Your wall cost is half your basement cost. The wall if you build it will cost less than half a contracted concrete wall. But... add up the whole picture and to save, you need to do all the labor and hunt for deals, on all items. IE faucets Home Depot regularly dump in the trash or sell for dollars due to new sku.

I would self build the ICF if I was you. You can do it.

Then, you save on E for the rest of...

bpf150,
Remember that there are as many opinions as there are people out here. Take the advise that works most closely for you and run with it. I am not really sure what we are thinking when we try to build a 200 year house. Things change. people change, taste will change. For that matter, the code will change. Dude, the people saying to use concrete walls and such are biased to the current status quo. Whatever. Build it, live in it and enjoy it. I've built on "conventional" foundations, 6x6 and 8x8 post in the ground and "frost protected shallow all weather wood". They all work.

We live in an earthquake prone area. The last thing I want is cracked concrete. Wood moves and flexes with the ground movement but that is not usually considered. Folks just seem to get focused on the mantra that wood rots and concrete lasts forever. Again I will adamantly say "whatever".

That said, we currently have a shallow, frost protected AWW foundation that is working great in Alaska. This is a 2 foot tall AWW crawl space foundation with 4" of foam board up the wall and laying 4 foot horizontal. "because the ground is prone to heaving". 3 years and the walls are perfectly level. Our other "professionally" built house has cracks in the basement floor already. They are concrete of course since no "self respecting" contractor would build a wood foundation.

But hey, I am just a new member with a little practical experience so who am I to contradict an advanced member or "professional" guy. Common sense has surely given way to government expertise.

Rick

Why build anything underground? Use frost protection and build almost everything above ground. With wood or concrete, depending on preferences.

Good point, basements are overrated. But here in Minnesota, the frost goes deep and even when it doesn't frost protected footing often won't get you down to the good virgin soil.

Posted By jonr on 08 Jul 2010 08:42 AM
Why build anything underground?

Tornadoes.  That is one of the main reasons I'm installing a basement.

But with above grade ICF walls, you are safe from windstorms without a basement. I would argue you are safer than in a basement of a wood framed house since all the wood framing would end up in the basement.

Your odds of dying from a tornado are about the same as from lightning and way lower than fire, electrocution or falling down those stairs to the basement. If you are worried about it, a safe room would also protect from much more likely things.

The quesion "Why build anything underground?" was asked. I provided an answer.

I take it you guys don't live where tornadoes are prevalent. If you've ever been in one like I have (fortunately we were in a musty old storm cellar at the time many years ago), I think your views might change.

If I was building on flat ground where I had to have the basement completely underground, I probably would not go with a basement, but rather a saferoom. The place where I am building offers an excellent layout for a walkout basement with a view of the river to the south. And I'm going with ICF walls from footings to roof.