OP
jim gerken
New member
Wow, thanks for all the input!
The 10 inches of foam under the slab certainly seems like overkill. Then I read the article and they told that on top of the concrete they put PT sleepers and more rigid foam. Holy smokes batman. It would be ice to know what the payback period is on that idea. Too many variables to guestimate. Regardless, 3 inch XPS is what I have.
Garage same level...We are trying to create a barrier free home, so wish to avoid a step up. Many many tuck under garages are on the same level as the house basement (in our area), and I lived in one for a while. That was 35 years ago. Today's cars leak and vaporize much less fuel than the cars of the 70s and 80s, maybe it is not as much of a factor anymore. At the time I lived in that home I did not notice a problem. The wife will not go back to detached garage like we have now in our home.
RFH and mini splits... you hit a hot topic with this. I have been tossing this around for a while. First, I love radiant floor heat. I have it in two workshop buildings with footed slabs (very similar construction to this proposed house plan). It's comfortable and efficient, and quiet. But there are drawbacks. Concrete slab complexity, where the tubing can be damaged during or anytime after pour, and ruin the workability of the system. I have not had this happen yet, but it ciuld, and this being a house there is not really any room for a screw up like that. Also, ac must be seperate. So in my workshops I put window units in the wall. For the house it would be mini splits. The floor plan is not wide open so I guess I'd need four minis, and that would leave four rooms with none. If I left doors open, the heat would find its way around, but I have read that humidity curiously does not flow out of non serviced rooms that well. Also, I'd really like to have continously recirculation and filtering, and complete distibution of incoming fresh air. No way around it in my mind, that means ductwork. Also, the cost of a RFH system combined with four mini splits is the same or more than a hi efficiency furnace and heat pump for AC and cool season heat. Both the RFH and the furnace require LP, no natural gas here, and both the mini splits and the heat pump use electricity, at about seer 18. The big difference is air quality. With ductwork I can blend HRV supplidd fresh air and distribute it better after filtering. Every room will be the same temp and humidity. Seems like the right way to go.
BUILDERMC what is the 4 inch barrier between slabs you are talking about? I met with the building inspector before anyone else and he did not see a problem with the plan. I will ask him again if you can give more detail. Thanks..
Septic flow downhill... yes, this is a hot button too. I literally will not build on this lot if pumping my chit uphill is the only way to do it. I also refuse to pay for a mound system. I told the designer that came out to find a suitable drain field location, that if he could not design a gravity flow system with no mound, I would not build it. He did find an area that will work if I have to build new. If I had done the walkout basement idea, the septic system would have been new, because we would have been too far away and 12 feet below the existing system. With the on grade one level home plan, we stand a chance to use the old system.
The garage is existing. It is 24x48, so I guess that's big enough. It's not in the right location, so luckily (?) the slab on grade construction of it was done poorly. It was poured without a vapor barrier nor any foam under it, so it sweats every day it is not frozen. Anything we park in it rusts and stinks. We found a guy who will pick it up and allow us to break up the crappy uneven broken concrete floor, then bring it back onto a footed kneewall. We plan to vapor barrier and foam board under the new floor of course. And probably will need 16 inches of sand too. That should dry it up in there.
Besides this large garage, there is a 32x45 pole she'd with concrete floor we recently re-tinned, plus a brand new 35x60 RFH shop, plus another older 25x96 pole she'd on the site. I think I will get by just fine without a basement closet.
The 10 inches of foam under the slab certainly seems like overkill. Then I read the article and they told that on top of the concrete they put PT sleepers and more rigid foam. Holy smokes batman. It would be ice to know what the payback period is on that idea. Too many variables to guestimate. Regardless, 3 inch XPS is what I have.
Garage same level...We are trying to create a barrier free home, so wish to avoid a step up. Many many tuck under garages are on the same level as the house basement (in our area), and I lived in one for a while. That was 35 years ago. Today's cars leak and vaporize much less fuel than the cars of the 70s and 80s, maybe it is not as much of a factor anymore. At the time I lived in that home I did not notice a problem. The wife will not go back to detached garage like we have now in our home.
RFH and mini splits... you hit a hot topic with this. I have been tossing this around for a while. First, I love radiant floor heat. I have it in two workshop buildings with footed slabs (very similar construction to this proposed house plan). It's comfortable and efficient, and quiet. But there are drawbacks. Concrete slab complexity, where the tubing can be damaged during or anytime after pour, and ruin the workability of the system. I have not had this happen yet, but it ciuld, and this being a house there is not really any room for a screw up like that. Also, ac must be seperate. So in my workshops I put window units in the wall. For the house it would be mini splits. The floor plan is not wide open so I guess I'd need four minis, and that would leave four rooms with none. If I left doors open, the heat would find its way around, but I have read that humidity curiously does not flow out of non serviced rooms that well. Also, I'd really like to have continously recirculation and filtering, and complete distibution of incoming fresh air. No way around it in my mind, that means ductwork. Also, the cost of a RFH system combined with four mini splits is the same or more than a hi efficiency furnace and heat pump for AC and cool season heat. Both the RFH and the furnace require LP, no natural gas here, and both the mini splits and the heat pump use electricity, at about seer 18. The big difference is air quality. With ductwork I can blend HRV supplidd fresh air and distribute it better after filtering. Every room will be the same temp and humidity. Seems like the right way to go.
BUILDERMC what is the 4 inch barrier between slabs you are talking about? I met with the building inspector before anyone else and he did not see a problem with the plan. I will ask him again if you can give more detail. Thanks..
Septic flow downhill... yes, this is a hot button too. I literally will not build on this lot if pumping my chit uphill is the only way to do it. I also refuse to pay for a mound system. I told the designer that came out to find a suitable drain field location, that if he could not design a gravity flow system with no mound, I would not build it. He did find an area that will work if I have to build new. If I had done the walkout basement idea, the septic system would have been new, because we would have been too far away and 12 feet below the existing system. With the on grade one level home plan, we stand a chance to use the old system.
The garage is existing. It is 24x48, so I guess that's big enough. It's not in the right location, so luckily (?) the slab on grade construction of it was done poorly. It was poured without a vapor barrier nor any foam under it, so it sweats every day it is not frozen. Anything we park in it rusts and stinks. We found a guy who will pick it up and allow us to break up the crappy uneven broken concrete floor, then bring it back onto a footed kneewall. We plan to vapor barrier and foam board under the new floor of course. And probably will need 16 inches of sand too. That should dry it up in there.
Besides this large garage, there is a 32x45 pole she'd with concrete floor we recently re-tinned, plus a brand new 35x60 RFH shop, plus another older 25x96 pole she'd on the site. I think I will get by just fine without a basement closet.
r #2 take it down and replace it:hissyfit:. Pitching the slab will take care of most of the run off but not all. As Gary said you'll will need to create a ramp if your looking for no transition from garage to house. Also sometimes the inspector when he is doing his inspection misses things that doesn't mean that just because he didn't pick up on it that it makes it right. In the end you are the one that needs to make sure things are correct.
