Your thoughts on my basement plans

[GPintheMitten]

It doesn't matter if it will actually float or not. What matters is whether the hydrostatic pressures and other forces will create a crack or lift of a section big enough to allow water in.

Frankly this is a stupid idea and shouldn't be entertained longer than a few hours.

Eddie is a carpenter craftsman remodeler, but he is not a home builder. Let a foundation expert do the job for you.

 

[jk96]

It doesn't matter if it will actually float or not. What matters is whether the hydrostatic pressures and other forces will create a crack or lift of a section big enough to allow water in.

Frankly this is a stupid idea and shouldn't be entertained longer than a few hours.

Eddie is a carpenter craftsman remodeler, but he is not a home builder. Let a foundation expert do the job for you.

Eddie GP said what everyone else is thinking but being nice enough not to put it in print. You mention Mike Holmes often. I think he would be laughing at you on this one. Sorry.

 

[jk96]

Eddie in re-reading my post my comment sounds harsh and that was not my intent. I have a huge respect for the quality of work on all of your projects. I think that is the reason the idea is so peplexing to myself and others.

 

[EarPlug]

Then build up the inner walls with 3/4 plywood and brace it all up against each wall without any forms on the outside, just the same rubber membrane up against the dirt walls of the hole. Then pour concrete into the wall cavities and when dry, remove the bracing, but leave the plywood for interior walls.

What is going to maintain the position and integrity of the membrane during the pouring if the concrete? There is going to be a lot of pressure trying to move, twist, poke and stretch the membrane as it conforms to the dirt walls.

 

[Gator6x4]

I think your plan will probably work Eddie. Have you considered using Landfill Liner?

Landfill Liner and Cover Systems-The Geomembrane - NYS Dept. of Environmental Conservation

http://www.nyfederation.org/PDF2012/27 HasemeierR.pdf

If I was going to try such, I would fabricate metal fasteners to imbed into the cement and then fasten to the back of the interior wall with screws or bolts that would allow for removal and replacement of a panel in the event a panel became damaged.

 

[forgeblast]

What about talking with a civil engineer, or dropping the group that did Harvey's testing for the ubunto box house they should know local terrain.

 

[riptides]

Poor drainage around the construction site was root cause.

Note the red clay soil makeup.



Note the float!

 

[EddieWalker]

Thank you for the link Gator, that's along the lines of my thinking.

While I still have serious doubts about the basement lifting from the water pressure when there will be no place for water to build up, I have considered creating a bell at the bottom of the footings and wall. It would be simple enough to hand dig out the bottom of the walls to create the bell, it wouldn't matter to the rubber liner, and the additional expense in concrete would be acceptable. This also has me wondering about friction of the walls holding the basement in place. In all the links I looked at about basements and swimming pools that have come out of the ground, they where all held in place by gravity. Not factoring in how much water was in the gravel or sand or fill soil around them, the common factor besides allowing that water in there is that none of them where held in place. I think that a poured wall that uses the dirt as the outside form will also hold that foundation in place. Thinking this through, it would appear to support my idea.

My thought on getting the liner to work is pretty straight forward. It comes in widths of 15 feet and as long as you could want it. I would buy one length 15 feet wide and 40 feet long. I would lay that section across the bottom of the hole and up the walls with the extra laying on the ground outside the hole. then I would get two pieces 15 foot wide by 20 feet long for the other two sides. There are several solvents or specialty glues out there that have lifetime warranties. With over a foot of overlap, I would form the liner along the other side, then glue it together. I've done this with koi ponds and it's a pain in the but to work with, but on a sunny day, it becomes very pliable and fairly easy to mold into place.

I will pour the floor first and let the weight of the concrete pull the liner down into position. Then after tying all the rebar together, I will build the interior forms and then fill with concrete. None of this sounds very difficult, I just have to take my time to get it right.

I like the idea of a backup in case of failure. It would be pretty simple to dig a hole into the floor area off to an out of the way corner big enough for a basin for a sump pump. That will take a little more effort to get the liner to fit into there, but like anything, I'll just stick with it until I get it done. I will fill the basin with sand and form it out so concrete does not cover it up, then install a cover over it. If I find there to be a leak into the liner, this will be the lowest spot of the liner and where the water will accumulate. If that happens, then all I will have to do is buy a sump pump. I will have power in the room, but might also look into a 12volt backup system in case the power fails during an extreme storm. This could easily be located under the stairs.

 

[EddieWalker]

Thank you for the link Gator, that's along the lines of my thinking.

While I still have serious doubts about the basement lifting from the water pressure when there will be no place for water to build up, I have considered creating a bell at the bottom of the footings and wall. It would be simple enough to hand dig out the bottom of the walls to create the bell, it wouldn't matter to the rubber liner, and the additional expense in concrete would be acceptable. This also has me wondering about friction of the walls holding the basement in place. In all the links I looked at about basements and swimming pools that have come out of the ground, they where all held in place by gravity. Not factoring in how much water was in the gravel or sand or fill soil around them, the common factor besides allowing that water in there is that none of them where held in place. I think that a poured wall that uses the dirt as the outside form will also hold that foundation in place. Thinking this through, it would appear to support my idea.

My thought on getting the liner to work is pretty straight forward. It comes in widths of 15 feet and as long as you could want it. I would buy one length 15 feet wide and 40 feet long. I would lay that section across the bottom of the hole and up the walls with the extra laying on the ground outside the hole. then I would get two pieces 15 foot wide by 20 feet long for the other two sides. There are several solvents or specialty glues out there that have lifetime warranties. With over a foot of overlap, I would form the liner along the other side, then glue it together. I've done this with koi ponds and it's a pain in the but to work with, but on a sunny day, it becomes very pliable and fairly easy to mold into place.

I will pour the floor first and let the weight of the concrete pull the liner down into position. Then after tying all the rebar together, I will build the interior forms and then fill with concrete. None of this sounds very difficult, I just have to take my time to get it right.

I like the idea of a backup in case of failure. It would be pretty simple to dig a hole into the floor area off to an out of the way corner big enough for a basin for a sump pump. That will take a little more effort to get the liner to fit into there, but like anything, I'll just stick with it until I get it done. I will fill the basin with sand and form it out so concrete does not cover it up, then install a cover over it. If I find there to be a leak into the liner, this will be the lowest spot of the liner and where the water will accumulate. If that happens, then all I will have to do is buy a sump pump. I will have power in the room, but might also look into a 12volt backup system in case the power fails during an extreme storm. This could easily be located under the stairs.

 

[jk96]

How are you keeping any water from getting between the liner and concrete?