Help: Pool deck causing moisture issues in house

poolnovice1

Bronze Supporter
May 11, 2018
108
Houston
Sorry see now but you would still benefit from a sump pump anywhere on that level where you can afford little space and not be an obstruction.
Frankly, I've sunk enough money into it. I've done what I can to control surface water. Next step is installing new floors with a moisture barrier. If we have moisture damage again, I'm making a flood claim. It's time for the insurance company to pony up at that point.
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
3,115
Spring Valley, NY
The sump pump is not very expensive at all. Dig a hole drop the crock into the pit with some gravel, drop an inexpensive $150-200- pump with 11/2" pipe and check valve piped to the outside.
 

A.O.

Well-known member
Apr 12, 2016
516
Kershaw, South Carolina
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
The sump pump is not very expensive at all. Dig a hole drop the crock into the pit with some gravel, drop an inexpensive $150-200- pump with 11/2" pipe and check valve piped to the outside.
I'm thinking digging that hole inside in a ground level slab would be a bit of a problem.
 

JamesW

TFP Expert
Mar 2, 2011
28,209
I would dig a hole in the triangle area about 5 feet deep and use a submersible pump to keep the ground water under control.

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superuser

Well-known member
Nov 16, 2020
204
Spring, TX
I'm reasonably confident those channel drains will resolve the issue.

Houston is a bit different than many parts of the country. Typical homes are built using post-tensioned slab-on-grade construction. We have no basements, or any portion of the home sub-grade (with very few exceptions). Most homes built in the last couple decades are also built up above street level at least a foot or two, as the streets are designed to act as flood channels when the storm drains and bayous overflow. So while our water table is comparatively pretty high, adjacent to the house you'd still have to dig a bit to find water. Along the same lines, if the water table were high enough to reach the slab, ground water would be weeping out of the ground at the street.

We actually have the reverse problem. If you don't regularly water the ground around your slab, you begin to have leveling problems due to the dirt drying and shrinking. You end up with parts of your house unevenly sinking into the ground, cracks in walls, doors and windows that stick, etc. Fixing it means digging under the beam of the slab and using a hydraulic press to drive concrete cylinders into the ground until you can use them to lift the house back to level. We aren't built on bedrock around here, it's all dirt and clay.
 
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poolnovice1

Bronze Supporter
May 11, 2018
108
Houston
I'm reasonably confident those channel drains will resolve the issue.

Houston is a bit different than many parts of the country. Typical homes are built using post-tensioned slab-on-grade construction. We have no basements, or any portion of the home sub-grade (with very few exceptions). Most homes built in the last couple decades are also built up above street level at least a foot or two, as the streets are designed to act as flood channels when the storm drains and bayous overflow. So while our water table is comparatively pretty high, adjacent to the house you'd still have to dig a bit to find water. Along the same lines, if the water table were high enough to reach the slab, ground water would be weeping out of the ground at the street.

We actually have the reverse problem. If you don't regularly water the ground around your slab, you begin to have leveling problems due to the dirt drying and shrinking. You end up with parts of your house unevenly sinking into the ground, cracks in walls, doors and windows that stick, etc. Fixing it means digging under the beam of the slab and using a hydraulic press to drive concrete cylinders into the ground until you can use them to lift the house back to level. We aren't built on bedrock around here, it's all dirt and clay.
One of our neighbors had foundation problems because his soil dried out during the dry spell we had in Houston a while back. His house was splitting in half and they had to do foundation repair.

My house is built up a foot or two above street level. The front yard slopes nicely out to the street. Unfortunately the deck slopes towards the house (doh!).

Needless to say, Houston climate and soil conditions are very challenging for homeowners.
 

JamesW

TFP Expert
Mar 2, 2011
28,209
I think that you mostly need to prevent oversaturation during heavy rainfall.

By selectively draining before and during a heavy rainfall, you can probably minimize water damage without drying out the ground too much.
 

poolnovice1

Bronze Supporter
May 11, 2018
108
Houston
I think that you mostly need to prevent oversaturation during heavy rainfall.

By selectively draining before and during a heavy rainfall, you can probably minimize water damage without drying out the ground too much.
But why a pump in that corner? It's not wet there. A pump there would drain water from that area only and have no effect anywhere else on the property..
 

superuser

Well-known member
Nov 16, 2020
204
Spring, TX
One of our neighbors had foundation problems because his soil dried out during the dry spell we had in Houston a while back. His house was splitting in half and they had to do foundation repair.

My house is built up a foot or two above street level. The front yard slopes nicely out to the street. Unfortunately the deck slopes towards the house (doh!).

Needless to say, Houston climate and soil conditions are very challenging for homeowners.
I had to pier my house in Katy, and they found piers the previous owner installed while doing the job. My house in Cypress started showing signs after 10 years, brought out an engineer and they said it was still within limits. So far my house in Spring is doing fine, but you know the drill. It's not if, it's when. The trick is to never let it get so bad the slab opens up. Gotta watch those expansion joints in the brick, they're kinda your early warning indicator.

How did the new drains look with yesterday's rain?
 

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poolnovice1

Bronze Supporter
May 11, 2018
108
Houston
I had to pier my house in Katy, and they found piers the previous owner installed while doing the job. My house in Cypress started showing signs after 10 years, brought out an engineer and they said it was still within limits. So far my house in Spring is doing fine, but you know the drill. It's not if, it's when. The trick is to never let it get so bad the slab opens up. Gotta watch those expansion joints in the brick, they're kinda your early warning indicator.

How did the new drains look with yesterday's rain?
What do you think about my expansion joint? The previous owner seems to have filled it with mortar.

The drains worked great. All water was drained out nicely.

We do have tiles that have cracked across the house in a near straight line. The crack is very thin. The previous owner said they cracked in the early 2000s. The cracks have not gotten worse and so we've just chalked it up to normal settlement.

This was our first home. I knew nothing about this stuff. I've learned a lot the hard way.
 

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superuser

Well-known member
Nov 16, 2020
204
Spring, TX
If it's filled with mortar I'd question why. The joint should be filled with a foam backer rod and sealed with polyurethane or silicone caulk to allow normal movement with thermal expansion. It might mean there was enough movement to pull the caulk away. It does look like the top is opening up while the bottom is still closed. That's the typical sign the slab is starting to move, so you may want to see if you can bring out a foundation repair company that will do a free evaluation. The process is pretty simple, they diagram the house and walk a water level around inside the perimeter to measure deflection from the mid-point of the house.

Hairline cracks in the tiles are another indicator, but as long as they stay closed they aren't anything to really worry about. You typically don't need to remedy until you see cracks in the slab open up an 1/8", or become unlevel. This house had a couple of those tiny hairline cracks in the tile too, but we had the slab measured during the inspection and everything was within 1/4" corner to corner. We pulled up the entire first floor tile during our remodel this year, and didn't find any cracks in the slab in those areas where the tile had cracked. So sometimes it is just the tile and nothing with the slab. Speaking of flooring, we installed wood look porcelain throughout the first floor and it looks great. Doesn't matter if it gets wet, very nice when we have people going in and out from the pool.
 
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superuser

Well-known member
Nov 16, 2020
204
Spring, TX
Looking at the photo again, I'm curious why the joint doesn't extend through that top row of bricks. Looks like it cracked through the mortar one brick to the left? I'm no expert on how brickwork is done, but going by the three houses I've owned in the area over the past 20-something years, the joints always ran clear to the soffit or Hardiplank.
 

JamesW

TFP Expert
Mar 2, 2011
28,209
Where do the new drains drain to?

Ground water typically migrates underground.

So, controlling it in one location should control it in all locations.
 

poolnovice1

Bronze Supporter
May 11, 2018
108
Houston
If it's filled with mortar I'd question why. The joint should be filled with a foam backer rod and sealed with polyurethane or silicone caulk to allow normal movement with thermal expansion. It might mean there was enough movement to pull the caulk away. It does look like the top is opening up while the bottom is still closed. That's the typical sign the slab is starting to move, so you may want to see if you can bring out a foundation repair company that will do a free evaluation. The process is pretty simple, they diagram the house and walk a water level around inside the perimeter to measure deflection from the mid-point of the house.

Hairline cracks in the tiles are another indicator, but as long as they stay closed they aren't anything to really worry about. You typically don't need to remedy until you see cracks in the slab open up an 1/8", or become unlevel. This house had a couple of those tiny hairline cracks in the tile too, but we had the slab measured during the inspection and everything was within 1/4" corner to corner. We pulled up the entire first floor tile during our remodel this year, and didn't find any cracks in the slab in those areas where the tile had cracked. So sometimes it is just the tile and nothing with the slab. Speaking of flooring, we installed wood look porcelain throughout the first floor and it looks great. Doesn't matter if it gets wet, very nice when we have people going in and out from the pool.
It looks like the mortar is just on the surface of it. I think it'll probably just chip out with a screwdriver, or might use a dremel. I'll then caulk it back up.

I've been thinking about getting a PE out here to evaluate the foundation. I should've done it before I bought the house. Our home inspector at the time said it "looked normal" and was just settlement. I've learned you really can't rely on home inspectors. They charge $500 to find little maintenance issues but miss the big things like foundations and deck/yard slope. Next house I buy, I'm hiring a PE from the get go.
 
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