Walkout basement...concrete or wood wall?

[jimtheengineer10]

For a walkout basement I typically call out a frost wall with a wood stud wall on top of the frost wall for the walkout side of the basement. However, my client is asking about constructing the walkout side wall out of concrete. The client would like to have a 10' basement ceiling height so the total concrete would be approximately 14' with the wall and the frost wall. Is this a good idea or should I advise them to go with a frost wall and then a wood stud wall? Thank you.

 

[concretemasonry]

Nothing wrong with a wall that high. The concrete portion is far stronger than a wood frame wall. It only takes a minimal amount of reinforcement (if any) to far exceed the strength of a wood wall.

Apparently, the owner wants to get some thermal mass to match the rest of the basement thermally. A wood frame wall would cool off much faster because of thermal stability.

I have townhouse with a walk-out slider (super efficient) and the 3 remaining walls are concrete (exterior and interior). The wood frame wall is a cold wall in the winter even with a lot of insulation the allows short term swings in the interior temperature. The good thing about the wood wall is that you get to feel and enjoy the noise and effects of storms and wind outside without actually being there.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[oldestguy]

A common technique in Wisconsin is to insulate the outside of the concrete with closed cell foam sheets at least an inch think. Cover it with wood or paint on some mortar. For a basement fully encased in thus manner, including under the slab, , the living conditions inside are much more comfortable the year around.

 

[shobroco]

Your concrete guys are not going to pour a wall 14' high in one lift, especially if they typically only do house basements. If the wall is prohibitively expensive you can keep the footings the same level throughout, & insulate them for frost. Far easier to design and build, and costs quite a bit less than stepped footings. Also no deep backfill for worries about poor compaction.

 

[concretemasonry]

shobroco -

That type of construction normally does not require a single wall 14' high to be constructed in a single pour or "lift". Poring a 10' high concrete wall offers no benefits since it is actually a wall built in segments. Actually, a properly detailed structural system would break the 14' into two wall segments with a slab providing lateral restrict that affects the loads on the walls and permits better construction.

For a home with a walk-out basement, it is usually on a hillside site with some grade differences that require stepped footing and sequenced construction over several days.

It would take a very unusual situation for a 14' high wall formed and poured. Even concrete masonry would provide a superior and more economical system based on the normal availability of 10' high wall forms and the traditional requirements of grouting in prescribed lift heights that is easily done with the common use of pumps for grout (not concrete) IF the owner insists on a high mass wall.

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[jimtheengineer10]

So they would pour the 4' frost wall and slab and then pour the 10' basement wall after? Do you typically have some #6 rebar @ 24" o.c. sticking up from the footing to basically dowel the basement and wall and frost wall together? Also, there would be a min. of three rows of horizontal #4 bars.

Thanks for the help.

 

[irishmustachio]

If one was already using hydronic type in floor heat for the walkout floor slab, would it be feasible to also pour one loop of lex through the footing and insulate accordingly, tie it in to to same system but regulated separately on it's own zone, and not worry about pilings beneath the footing where not below grade, and eliminate the frost wall below the footing for the wood wall on the walk out side?

SK Canada...since it kind of matters.

 

[darthsoilsguy2]

If the big seller to the Client is the thermal consistency, you should check out Insulated Concrete Forms, or ICFs.

i designed some foundations with this and was really jealous of those units after they were built.

http://www.arxx.com/

 

[geotechnicalenginee]

• That’s not bad but I agree that a frost wall is better than a wood stud wall.
• I have done frost walls twice and I must say that my clients prefer it. I don’t think a wood stud wall is good.
• A frost wall is way better. But if your client insists on a wood stud wall, then you should do what oldestguy said.
• You should follow your client even if you know that a frost wall is better. He might look for another engineer if you don’t follow him.
• One way to be successful is to follow what your client wants. Even if you think his idea is not good, still do what he wants. Your job depends on that.