Opinions on hybrid slab foundation.

[dmccarty]

...
My primary concern is that my daughter's house is going to be 2 stories. (I live in a 90 year old two story house.......I think they are a bad idea too). The issue is that if the first floor is a slab there is nowhere to run ducting and it will have to come down from the attic and run through the ceiling space between the floors.

Yeah, I don't like two story houses either.

If we were building today, I would look closely at the split HVAC units. You can set up zones in the house with these things. They just run the coolant pipes to the zone units so it is easy to hide the pipes. One can use ceiling details like coffered or tray ceilings to hide duct work. We thought about having soffits, somehow that seems like the wrong word, along the ceilings to hold lights and as a detail. Did not do it because it was not needed but it would work real well with split HVAC units.

Later,
Dan

 

[dmccarty]

My brother's first home was slab neighborhood built in 1948.

65 years in it was common for the copper water pipes to leak... seemed someone in the neighborhood was always chasing a leak... the home 10k homes in 1948 where selling for 650k 65 years later.

When we remodeled and added I put all the water pipe overhead... worked well but needs to be well insulated.

Next door neighbor had the same done on 200k remodel and the first weekend the new copper water pipe froze and destroyed the ceiling and maple floor... it had a drop for an outside hydrant right at an eve vent.

There is a copper pipe rated for installation in concrete. I have no idea if that was available back in the 40's. Having said that, my grandmothers house was built in the late 40's or 50's and had copper. I am pretty sure the copper was in the slab and she did not have any problems in the 40-50 years she lived in the house so maybe they did have copper rated for concrete back then or she got lucky.

I should have mentioned that our waste lines are the only plumbing in the slab. The supply lines are PEX and run in the attic under the insulation and all but on top of the ceiling. No problems with freezing. The insulation is R35 or 40. We have had the water line sorta freeze up once when it got below 10 degrees. It was where the supply line enters the house and NOT in the attic. Thankfully no issues and now I put a heater in that area when we go below 10f.

Later,
Dan

 

[Gary Fowler]

That is how my house and shop were built. Grade beam was poured, then concrete blocks set on the grade beam and these were used for the slab form. Compacted sand was then placed inside the forms for the plumbing to lay in. Everything inside the forms was original compacted native soil. No settlement has occurred in the 8 years we have lived here Our contractor builds everything that way.

Note the black pipe is foam insulation for the water lines. We installed a hot water circulation system to each water station so we have basically instant hot water for sink and shower. The only station that isn't constantly circulated is the kitchen sink and middle bathroom since they are only about 10 feet from the hot water heater. I love this since the master bath is about 50 feet from the hot water but it only takes about 3 seconds to get hot water (distance from slab to faucet).

 

[Oldpath05]

("A basement is a poorly lighted damp hole in the ground that consumes many resources to convert it into habital living space.")<<<<<WRONG as rain Batman, my basement is very use and nowhere's near finished, to me my basement is invaluable, especially with a wood fired furnace, my wife is down there right now on a treadmill.

 

[N80]

I don't think we need heated floors here.

I think running the pex in pipe chases is a great idea.

I do not like basements. I'm sure there are good ones......but I haven't been in many and have never owned a good one. My current (90 year old) basement is a mess. All remedies would be crazy expensive and probably temporary.

Regardless, my daughter is not interested in a basement and their lot is flat so it wouldn't be a walk-in basement anyway.

I like the split unit HVAC solutions. My wife and daughter "don't like the way they look". They are also quite expensive. That's what I'd do if I were building...traditional upstairs, split units downstairs.