dave1949
Super Star Member
No doubt about that. All slab problems tend to be big problems. What's up with basements in Alabama? Too many humidy problems? Drainage?
Dave.
New house questions
- Thread starter luscsmith
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No doubt about that. All slab problems tend to be big problems. What's up with basements in Alabama? Too many humidy problems? Drainage?
Dave.
woodchuckie
Platinum Member
There are lots of basements and unless it's a hole with four sides the moisture isn't a problem with proper landscaping.
Just an afterthought, In the late 40's and early 50's the walls in new houses weren't insulated. They did have a few inches of insulation in the attic.
Just an afterthought, In the late 40's and early 50's the walls in new houses weren't insulated. They did have a few inches of insulation in the attic.
dave1949
Super Star Member
The additional construction cost, especially up north where a 4' frost wall is needed, for a full basement compared to a crawl space is minimal. A basement can be inexpensive space by comparison. I guess down south you aren't putting in 4' frost walls and that would change the math considerably.
For access to plumbing, electric, ductwork, etc. a basement is hard to beat. Crawlspaces have too many spiders
Dave.
eepete
Platinum Member
My house in North Carolina is insulated with the spray in foam. The entire house, including the attic spaces, is interior space. On a 103 degree day, the attic temperature was 85 degrees. I have ducts in the attic space, but all equipment is in the basement. In this neck of the woods, if you insulate the entire house you must have a metal roof. If you do shingles, then the attics space must be open and vented. Our old house was that way, and on a 100 degree days the attic temperature was about 135 degrees.
I agree with the "insulation is gold" approach. Payback on the foam insulation in 6" exterior walls was about 8 years. So you don't see this much in spec houses. Re-doing or changing insulation is as impractical and expensive as moving a wall once the place is built, so do it right the 1st time.
We have a basement, but we are built into a hill. This means the footer drains actually work. Problems with basements here are when people put a hole with four walls in the clay soil and then wonder why it fills with water.
Pete
I agree with the "insulation is gold" approach. Payback on the foam insulation in 6" exterior walls was about 8 years. So you don't see this much in spec houses. Re-doing or changing insulation is as impractical and expensive as moving a wall once the place is built, so do it right the 1st time.
We have a basement, but we are built into a hill. This means the footer drains actually work. Problems with basements here are when people put a hole with four walls in the clay soil and then wonder why it fills with water.
Pete
dave1949
Super Star Member
I have seen pics and articles on insulated attics like you have. Never heard from anyone who owned them. Good to know it works out.
In a similar way, I have seen articles promoting incorporating a crawlspace into the house environment. Good vapor barrier on the ground, but insulated walls and no vents. Seeing any of that down your way?
Right on with the basements, there are no good basements without good drainage. They sure are useful if they are dry.
Dave.
dmccarty
Super Star Member
I prefer slabs. Our dream house we built has a colored concrete slab. The slab is our finished floor. From grade to the floor is about 12 inches on the up slope side of the house. The far down slope side is over 5 feet. The fill was 67 stone. NOTHING has moved.
All but one of the houses we and all of my family have lived in for decades have been slab. Never had a problem with the plumbing in a slab. Friends, neighbors all in slabs and never heard of problem. I am sure they exist but they certainly have not affected the neighborhoods we and my extended family have lived in across many states.
The problem with a wood floor over a crawl space or basement is that it is a wood floor. A coworker had to rip out her bathroom floor in a very new house because the toilet leaked and rotted out the wood. The toilet seal in our city leaked. It was a pain. It was not really a problem since the house was a slab. If it was on a crawl space I am sure I would have had to rip out the floor and insulation and replaced it. If your toilet plugs and floods you get to go deal with the floor issues in the house and in the insulation in the crawlspace/basement. This happened in our city house. I had to clean up the mess but that was all.
Our floor in our country house is colored finished concrete. It was cheap and durable. If we want to put down wood, slate, tile, etc, we can. Plus, you can use the concrete as mass to help heat and cool your house.
We built a passive solar heated house. It works. It was cheap and easy to do. I would work better if we did not want to see our land and put in huge windows, i.e., holes in the walls to get the views. But we do like the view and opening the windows as much as well can so it all balances out. A passive solar house and a slab are made for each other.
If you are going to build a house you NEED to read this book, http://www.buildingsciencepress.com/Builders-Guide-to-HotHumid-Climates-P2.aspx.
The author knows his stuff. I read what he had to say on many a builders forums when he was having conversations regarding building techniques, details and materials. Our house is built according to the details in his book. He has various books specific to the climate in different areas of the country. What works in the South will not work well in the North and vice versa.
Get his book. Read it. Also read the information on the Building Science website.
Lstiburek argues for insulated and humidity controlled attics AND crawl spaces. I think he is correct. However, and he will say this, getting his details approved by a building inspector can be interesting. We did not have to worry about the crawl space since we don't have one. I would have preferred to have treated the attic so that the heat and cold did not get into the space but I did not fight that battle with the inspectors.
One problem with insulating under the roof is the effect of the heat buildup on the roofing material. The life time and installation of the roofing material can be affected. Asphalt shingles can curl and warp if there is insulation under the roof deck. You have to check with the shingle maker to see what they say.
Houses in the south generally do not have basements since we the frost line is not that deep. In my area the frost line is not even 12 inches down. The reason basements are built up north is that they have to dig down so deep for the foundation so they might as well just have a basement. The only non slab house we ever lived in had a basement since we were so far north. The basement had water issues too.
Later,
Dan
All but one of the houses we and all of my family have lived in for decades have been slab. Never had a problem with the plumbing in a slab. Friends, neighbors all in slabs and never heard of problem. I am sure they exist but they certainly have not affected the neighborhoods we and my extended family have lived in across many states.
The problem with a wood floor over a crawl space or basement is that it is a wood floor.
A coworker had to rip out her bathroom floor in a very new house because the toilet leaked and rotted out the wood. The toilet seal in our city leaked. It was a pain. It was not really a problem since the house was a slab. If it was on a crawl space I am sure I would have had to rip out the floor and insulation and replaced it. If your toilet plugs and floods you get to go deal with the floor issues in the house and in the insulation in the crawlspace/basement. This happened in our city house. I had to clean up the mess but that was all. Our floor in our country house is colored finished concrete. It was cheap and durable. If we want to put down wood, slate, tile, etc, we can. Plus, you can use the concrete as mass to help heat and cool your house.
We built a passive solar heated house. It works. It was cheap and easy to do. I would work better if we did not want to see our land and put in huge windows, i.e., holes in the walls to get the views.
But we do like the view and opening the windows as much as well can so it all balances out. A passive solar house and a slab are made for each other. If you are going to build a house you NEED to read this book, http://www.buildingsciencepress.com/Builders-Guide-to-HotHumid-Climates-P2.aspx.
The author knows his stuff. I read what he had to say on many a builders forums when he was having conversations regarding building techniques, details and materials. Our house is built according to the details in his book. He has various books specific to the climate in different areas of the country. What works in the South will not work well in the North and vice versa.
Get his book. Read it. Also read the information on the Building Science website.
Lstiburek argues for insulated and humidity controlled attics AND crawl spaces. I think he is correct. However, and he will say this, getting his details approved by a building inspector can be interesting.
We did not have to worry about the crawl space since we don't have one. I would have preferred to have treated the attic so that the heat and cold did not get into the space but I did not fight that battle with the inspectors. One problem with insulating under the roof is the effect of the heat buildup on the roofing material. The life time and installation of the roofing material can be affected. Asphalt shingles can curl and warp if there is insulation under the roof deck. You have to check with the shingle maker to see what they say.
Houses in the south generally do not have basements since we the frost line is not that deep. In my area the frost line is not even 12 inches down. The reason basements are built up north is that they have to dig down so deep for the foundation so they might as well just have a basement. The only non slab house we ever lived in had a basement since we were so far north. The basement had water issues too.
Later,
Dan
20 20
Elite Member
Dmccarty; Just curious how long have you been on your slab? The reason I ask is because I have known of a couple of homes that sat great for some time{20yrs} with no trouble, THEN...... all poo hits the fan? I hope you have great luck with your slab, and enjoy the fact that there are so many different routes one can take for a foundation.
My parents house has been sitting on a flat{field} rock crawl space 4+' in the ground for over 100years. Of course back then they didn't have all these so called "helpfull regs" wonder how they ever lived? I've seen this and that about how some types of construction will hold up for blank amount of years. problem is they truely DON'T know how long they'll hold up because they've only been around for X amount of years. The sales pitch is what sell BS better then anything IMO.
My parents house has been sitting on a flat{field} rock crawl space 4+' in the ground for over 100years. Of course back then they didn't have all these so called "helpfull regs" wonder how they ever lived? I've seen this and that about how some types of construction will hold up for blank amount of years. problem is they truely DON'T know how long they'll hold up because they've only been around for X amount of years. The sales pitch is what sell BS better then anything IMO.
dave1949
Super Star Member
Dan:
Thanks for the book reference. I would be afraid to read it and find out what I may have done wrong We have passive solar with a slab floor too. I think for a passive solar home to be worthy of the name, it will have a slab. They are made for each other. That's the reason I have a slab, but a basement would be preferable if I could get the best of both worlds IMO.
20_20: What do you mean by all goes to poop? My slab is only 3 1/2 years old, no problems, but no guarantee of future either. I do have some confidence that short of an earthquake, it will be okay.
Lots of slab problems are related to plumbing and poor drainage. Use of copper in concrete and such. My son owns a mid-60's home on a slab with radiant heat running in copper. It's a local miracle and about the only one left in the neighborhood. The rest all developed leaks long ago and switched over to forced air primarily.
My supply plumbing is PEX, well below the slab. It was the first thing that went in on top of the excavated space. It has a protective layer of sand over it, then the rock drainage bed, then styrofoam, then the slab - which I put #5 rebar in on a 14" grid. Used extra tall chairs due to the thickness of the slab which is 8" min. The supply lines come through the slab inside 1" PVC conduit sleeves beginning with a gentle sweep up.
My radiant heat plumbing is PEX in the slab. I hope it lasts, it had a pretty good history in Europe before it became common here. If it doesn't, in a passive solar home I am not going to freeze anyways.
There are older commercially constructed slabs in this area that have no or few issues. I think the construction technique is the key to the whole thing.
There is no denying though, any slab problem tends to be a big problem by comparison to a crawlspace or basement. Of course, basement floors can have a lot of the same issues as slabs., but they aren't structural and don't have plumbing typically.
If you live in a northern climate, the slab methods described by boxygen are correct. As boxygen said, slabs are/were poorly understood, consequently many were poorly built and developed cracks and tilts. That gives them somewhat of a bad name among homebuyers around here. That's hard to overcome, plus New Englanders love their basements. They will take a damp basement over no basement.
Basements are great where a deep foundation is needed to begin with, but I personally wouldn't choose a basement in an area with a high water table or sketchy drainage. Or I would elevate the entire house to account for those factors and berm the basement walls as needed. That viewpoint comes from growing up in what used to the Great Black Swamp in NW Ohio.
Dave.
Thanks for the book reference. I would be afraid to read it and find out what I may have done wrong
We have passive solar with a slab floor too. I think for a passive solar home to be worthy of the name, it will have a slab. They are made for each other. That's the reason I have a slab, but a basement would be preferable if I could get the best of both worlds IMO.20_20: What do you mean by all goes to poop? My slab is only 3 1/2 years old, no problems, but no guarantee of future either. I do have some confidence that short of an earthquake, it will be okay.
Lots of slab problems are related to plumbing and poor drainage. Use of copper in concrete and such. My son owns a mid-60's home on a slab with radiant heat running in copper. It's a local miracle and about the only one left in the neighborhood. The rest all developed leaks long ago and switched over to forced air primarily.
My supply plumbing is PEX, well below the slab. It was the first thing that went in on top of the excavated space. It has a protective layer of sand over it, then the rock drainage bed, then styrofoam, then the slab - which I put #5 rebar in on a 14" grid. Used extra tall chairs due to the thickness of the slab which is 8" min. The supply lines come through the slab inside 1" PVC conduit sleeves beginning with a gentle sweep up.
My radiant heat plumbing is PEX in the slab. I hope it lasts, it had a pretty good history in Europe before it became common here. If it doesn't, in a passive solar home I am not going to freeze anyways.
There are older commercially constructed slabs in this area that have no or few issues. I think the construction technique is the key to the whole thing.
There is no denying though, any slab problem tends to be a big problem by comparison to a crawlspace or basement. Of course, basement floors can have a lot of the same issues as slabs., but they aren't structural and don't have plumbing typically.
If you live in a northern climate, the slab methods described by boxygen are correct. As boxygen said, slabs are/were poorly understood, consequently many were poorly built and developed cracks and tilts. That gives them somewhat of a bad name among homebuyers around here. That's hard to overcome, plus New Englanders love their basements. They will take a damp basement over no basement.
Basements are great where a deep foundation is needed to begin with, but I personally wouldn't choose a basement in an area with a high water table or sketchy drainage. Or I would elevate the entire house to account for those factors and berm the basement walls as needed. That viewpoint comes from growing up in what used to the Great Black Swamp in NW Ohio.
Dave.
herd
Gold Member
Actually, a slab house in these parts (or any slab structure) is more prone to termite infestation than crawl space structure. My Dad was a Pest Control Operator for 35 years and my younger brother has the business now. I have seen much termite infestation in slab. Here's what happens: most slabs are "filled and tamped" with sand, river clay, or some type of fill. The fill is not always clean and small sticks and debris can attract termites.
The debris is eaten by termites, or rots, and voids occur. In times, the voids become small hairline cracks, sometime much larger. Those cracks are the termite's entry points. Also, keyways or other types of crack management accessories become termite entry points.
In these parts, if you fill and tamp, you are guaranteeing termites. You can control it with a termite pre-treat, and then annual applications of a termiticide. Knowing this over the years, I have never built a house on a slab. I have two porches on my house, about 4' above grade. I used metal decking to suspend the floors and then poured concrete. It is a much better floor system and costs basically the same.
The debris is eaten by termites, or rots, and voids occur. In times, the voids become small hairline cracks, sometime much larger. Those cracks are the termite's entry points. Also, keyways or other types of crack management accessories become termite entry points.
In these parts, if you fill and tamp, you are guaranteeing termites. You can control it with a termite pre-treat, and then annual applications of a termiticide. Knowing this over the years, I have never built a house on a slab. I have two porches on my house, about 4' above grade. I used metal decking to suspend the floors and then poured concrete. It is a much better floor system and costs basically the same.
20 20
Elite Member
I am not trying to scare anyone, a properly done slab should last a long time. I believe the problem lys with poor construction methods. Friend of mine wanted to get an equity, house{double wide} was around 8-10 years. They wanted him to put block around the house 1st{instead of the skirting}. When he did this he found his slab had shifted allmost 1 foot from one end to the other{long home}. Another guy I know from down south had his house{stick built} on a slab for 20+years. Started having some plumbing issues, checked it out and found out the slab had cracked in one corner and started dropping everything. Another guy had his house{double wide} for a year toilet backed up, slab shifted messing up plumbing. There are many more of these stories but I don't want to panic or start a B fest with anyone. If you are doing a slab just make sure it is done right. Even a little shift in a slab that causes plumbing problems could easily turn out to be much worse down the road.
Foundations can be very frustrating and much of how they work relys on the ground their in. I say every situation is different and if it were me having a foundation put in, the foundation contractor better know something about the earth{dirt, sand, clay, rock, etc} AT MY BUILDING spot. Up here I can go from clay to swamp goop to sand to rock all in a very short distance. What may work for 1 would fall to pieces on 2.
Foundations can be very frustrating and much of how they work relys on the ground their in. I say every situation is different and if it were me having a foundation put in, the foundation contractor better know something about the earth{dirt, sand, clay, rock, etc} AT MY BUILDING spot. Up here I can go from clay to swamp goop to sand to rock all in a very short distance. What may work for 1 would fall to pieces on 2.