FASWALL construction blocks and foundation questio

[pforden]

Instead of framing most of our Grandfather Cottage, we are now planning to use FASWALL reinforced with rebar and concrete. There is a house of this material going up about five miles from our site and it looks good and appears very solid. We plan to put in concrete footings for the block.

Anyone have any comments on this type of construction? FASWALL is advertised as impervious to termites -- very attractive outside of Austin, Texas -- and we are also happy about the ability to stand strong winds.

The man who is going to do our dirt work plans to build up the soil in order to save nearby oaks. I am wondering if the concrete footings will settle or shift as the root systems of these trees change or decay over time. I hate to put money we don't have into an engineer for the foundation, but I have so many questions about what is best. We have little shade outside of the large grove where we want to put the house.

Penny

[glenn kangiser]

Seems the entire house will have to be engineered to use this system with only the shape and dimensions useable from the plans.  Possibly the engineer can adapt the roof structure over.  I don't see it as being the same animal though. :-/

[John Raabe]

"Faswall wall-forms (made of wood chip byproducts and concrete) are used as the forms for poured concrete walls. They are left in place to provide permanent insulation to the walls."

It is an interesting ICF (insulated concrete form) system. Here is MORE INFORMATION.

This is a specialized system done by a local FRANCHISEE who would provide the engineering needed for the building permit. I expect they would install the system and provide either a shell package (with roof in place) or just the wall package with you or your builder doing the rest.

Any specialized drawings from the local installer can be added to the Grandfather package and they will probably run the permit themselves using your Grandfather Cottage layout and any changes you have made.

Here's an example of a one-story stucco finished house;


An interesting way to go and please keep us informed. It should be a very reasonable choice for your area.

PS - You should not build footings over tree roots. You want to place all footings on inorganic soil that has not been disturbed or dug up (if you do you will have to compact the soil back to its initial density).

[pforden]

John,
Thanks for the input. It looks to us as if we can work with the contractor to put up the blocks, saving ourselves the cost of his crew, but the rebar and concrete is more complicated. For the house in our area of Bastrop County the walls are of FasWall up to 9' then there is a 3 foot pony wall and gable walls, insulated with treated cotton (recycled denim). The contractor writes to me that, "The slab you see actually has a layer of clay treated wood chips and the top layer mix is 70% FasWall chips.  This acts as kind of a breathable vapor barrier and neutralizes the electromagnetic problems with the calcium-oxide based cement.   The kitchen is getting tile, the center area is flagstone, with an interior mandala shaped garden, and the rest is bamboo.  The stucco on the walls is site mixed out of sifted sand and type-s Portland.  The roof panels are actually walk-in cooler panels.  Since the walls are so breathable and humidity balancing; the humidity problems with foam have vanished." This is a much more ambitious project than ours, of course. Also, the owner of that property is so committed to green that a huge pine is incorporated into the structure of the home.

Could we just go with a slab over the tree roots, or not build on them at all? We want to build into the woods, it is our only shade, really. We could go to the south of the woods outside of it, I guess, and put up arbors on the east.  We are low on money; footings seem like an okay foundation for this stuff; the slab price quoted by one person was an enormous amount of money in relation to the amount we can afford for the whole house.

I appreciate any input on the foundation, in general terms re: the trees, not so much in relation to the FasWall. All of the soil outside the woods is planted in coastal bermudagrass.

Thanks.
Penny

[John Raabe]

Penny:

The rule of thumb is to not build on any organic materials since it will rot, attract critters, etc. However, it sounds like you have a good crew to work with so I would see what they have to say about the foundation issues. Building a house is a short term destructive event for the site. However, longer term a well done house can improve the local environment. Life adjusts