our new home may have to be footed slab, no basement or crawlspace - input?

[jim gerken]

We drew a reasonable plan for a ranch with walkout basement, 1500 square feet per level. Due to use of ICF construction having foam exposed even the basement walls must be sheetrocked. Due to new code, the basement ceiling must also be sheetrocked. These plus other factors lead us to basically fully finishing the basement. Bids for this plan came back 50% over our budget. Wife started thinking, this house is for aging in place, so the stairs will eventually be a barrier to access the large storage closet called a basement.basement . She draws a new plan, pulling laundry and a studio room up from the basement to the main, and kicking the basement out completely. We re surveyed the lot and found that pulling the home away from the hillside onto level ground (cause the walkout basement is probably out), and by keeping all the plumbing on the main level, we may be able to use an existing septic system without pumping the waste uphill, saving $8000. Chopping off the basement saves a bunch too, and keeping the ICF walls makes it safe for storms without a basement. Part of the savings is the floor trusses we don't need, so that brings us to a slab floor.

The slab floor forces a few changes. HVAC was the first issue that I saw. Found plenum trusses described, so that looks like a good solution to keep ducts inside conditioned space, and out of the floor. Electrical is pretty easy overhead in the attic, no problem there. Plumbing mostly has to go in the floor, although the plenum truss will help that too somewhat.

Do you have any other good ideas for me, to help remember all the important things before the concrete hardens?

Efficiency wise, we are in good shape. As mentioned, ICF walls. 3 inches of XPS foam under slab. A couple inches of spray foam in the attic to seal eveything, then R50 blown in. Triple pane fiberglass windows and one door. Good quality fiberglass front door. High efficiency LP furnace and a heat pump ac unit. Heat exchanger (HRV) of course.

 

[kevinwak]

There are so man days that I wish we hadn't built the 1,500 sq ft shed below the house that we call a basement. One thing I would add when designing your build is make your new home wheelchair accessible. 36" doors and slightly wider halls, and a not cramped laundry room. When designing my house I had every intention to do this, even had many discussions with a wheelchair bound cousin, but the. For one reason or another all these features missed the plan. Our laundry room is cramped, two more feet would have added a small cost in building the house, but would have made a huge difference in The livability for years to come.

 

[Parkanzky]

If your plan was to "age in place," then you should never have considered putting the laundry in the basement. We moved my mother recently and one of the main reasons was that the laundry was in the basement of her ranch home. We're in our thirties and just purchased a home. Main-floor master and laundry were must-haves when we were shopping. We don't plan to have this home long enough that it's an issue, but you never know.

Our new home is an ICF construction walkout ranch with poured walls all the way from basement to the roof and foam insulation in the attic. There can be gale-force winds outside and you wouldn't know it in the house despite the cheap windows. You really can't beat the solid concrete walls for the prevention of air-incursion!

 

[jim gerken]

There are so man days that I wish we hadn't built the 1,500 sq ft shed below the house that we call a basement. One thing I would add when designing your build is make your new home wheelchair accessible. 36" doors and slightly wider halls, and a not cramped laundry room. When designing my house I had every intention to do this, even had many discussions with a wheelchair bound cousin, but the. For one reason or another all these features missed the plan. Our laundry room is cramped, two more feet would have added a small cost in building the house, but would have made a huge difference in The livability for years to come.

Thanks, good sanity check on the basement closet we are giving up. Yup, we have all 36 inch doors, and virtually no vertical barriers whatsoever. Even the attached garage floor is the same elevation as the house floor (is there any giant problem with that idea?). And our laundry room is also the utility room, and there is a lot of room to set up an iron board (yes, she irons!), plus more space for storage, and a nice window.

 

[dave1949]

This series in Fine Homebuilding on Passive House construction has some good slab insulation techniques IMO. Not sure if that helps or integrates well with ICF use. The biggest difference would be you isolate the slab from the outdoor temps but you still have the advantage of the durable exposed concrete frost wall. Food for thought.

The Passive House Build, Part 3: Superinsulated Slab - Fine Homebuilding Video

 

[CurlyDave]

This thread has many ideas along similar lines: http://www.tractorbynet.com/forums/projects/337740-building-retirement-place.html?highlight=

I am not a big fan of attached garages at the same level as the house. Gas fumes from cars. At least put a breezeway between.

Make the garage twice as big as you think you need and you will not miss the basement.

 

[ErikVann]

Did you considering slab radiant heat with mini split ac? Seems with all that thermal mass a radiant system would be nice.. Tough to beat the cozy consistent feel of radiant.

There are several ignition barrier paints that can be sprayed over foam In lieu of sheet rock. They are called entoumescent paints. When sprayed at certain thickness they fulfill many ignition barrier requirements.

 

[BuilderML]

With a slab i would strongly consider radiant in floor heat. If i had to do it over again i am not sure i would do a basement its over 3600 sq ft of closet. I wish i would have spent that dough on other things. Less excavation cost, less concrete. The big thing i see as a negative would be resale. Also, unless things are different in your area you'll need a 4" barrier from garage slab to house. Enjoy your build.:thumbsup:

 

[dave1949]

A septic system with a macerator (chit grinder) and lift pump would be something worth avoiding. Even if it adds a few $Ks to your building project for elevation of the slab you would be money and future maintenance problems ahead.

An article regarding how to cover the exposed ICF above grade:
How to Finish Exterior Foundation Insulation | GreenBuildingAdvisor.com

I think it is important to have a plan for an ICF protective covering that you are: happy with how it looks, is it durable, and is it maintenance free? Avoiding a covered pathway for insect travel from the ground to your framing is something to think about too.

 

[TCJatko]

Did you considering slab radiant heat with mini split ac? Seems with all that thermal mass a radiant system would be nice.. Tough to beat the cozy consistent feel of radiant.

There are several ignition barrier paints that can be sprayed over foam In lieu of sheet rock. They are called entoumescent paints. When sprayed at certain thickness they fulfill many ignition barrier requirements.

Agree with radiant heat. Keeps the feet nice and warm; you can turn down the thermostat a bit.