Raised concrete patio with drainage issues

[nitanee123]

I've got a raised concrete slab patio that is about 3 feet off the ground sitting on brick exterior and I'd guess the thickness of the pad is about 5 inches. It is adjacent to my house. It is approximately 12 feet x 15 feet. I do have a basement but the patio is not over top of the basement. This house/patio is about 25 years old and I am in Pennsylvania (which means colder winters, snow, ice). Since there is nothing directly underneath and it is 6 feet from the house and since it is sagging in the middle, I would suspect there is a just dirt underneath.

There is a low point in the patio that causes water to puddle when it rains. This low point is just about the dead center of the slab which puts it about 6 feet from my house.

I had a concrete guy come out and he suggest I either (a.) rip out the pad and put in a new one, or (b.) put a new pad over top of the existing pad. I've been waiting on a price from him for the last month. In the meantime, I've looked online and some people have said they simply drilled a hole in the slab to let it drain down.

Now I don't know much about home building or engineering but I am thinking it would be a cheap and easy fix. The downside would be that the concrete might crack further (there is a hairline crack already) and I might have to replace the slab altogether after a few years. (But if I need to change the pad anyway, why not try drilling the hold first?!)

Thoughts? Could I do damage to my house/foundation by doing this? Any other thoughts?

p.s. I did read where somebody put a polymer sealant to deal with their concrete issue. The low point is probably 1/2 of an inch lower than the rest of the slab so I think it may be too deep.

 

[WDLion]

I've got a raised concrete slab patio that is about 3 feet off the ground sitting on brick exterior) and I'd guess the thickness of the pad is about 5 inches. It is adjacent to my house. It is approximately 12 feet x 15 feet. I do have a basement but the patio is not over top of the basement. This house/patio is about 25 years old and I am in Pennsylvania (which means colder winters, snow, ice). Since there is not patio directly underneath and it is 6 feet from the house and since it is sagging in the middle, I would suspect there is a just dirt underneath.

There is a low point in the patio that causes water to puddle when it rains. This low point is just about the dead center of the slab which puts it about 6 feet from my house.

I had a concrete guy come out and he suggest I either (a.) rip out the pad and put in a new one, or (b.) put a new pad over top of the existing pad. I've been waiting on a price from him for the last month. In the meantime, I've looked online and some people have said they simply drilled a hole in the slab to let it drain down.

Now I don't know much about home building or engineering but I am thinking it would be a cheap and easy fix. The downside would be that the concrete might crack further (there is a hairline crack already) and I might have to replace the slab altogether after a few years. (But if I need to change the pad anyway, why not try drilling the hold first?!)

Thoughts? Could I do damage to my house/foundation by doing this? Any other thoughts?

p.s. I did read where somebody put a polymer sealant to deal with their concrete issue. The low point is probably 1/2 of an inch lower than the rest of the slab so I think it may be too deep.

Broom.

 

[nitanee123]

Broom.

I squeegee. And its getting old. And I can't put my outdoor furniture on the patio because it will be directly in the middle of this puddle.

 

[PS4814]

Can’t help on any of the engineering questions but I’d recommend getting some other contractors to look at it. It’s been my experience that if the guy hasn’t given you a quote in over a month that’s usually a clear sign that they’re not interested in doing the job and/or are too busy to take on the project for the foreseeable future.

 

[wilbury]

I've got a raised concrete slab patio that is about 3 feet off the ground sitting on brick exterior and I'd guess the thickness of the pad is about 5 inches. It is adjacent to my house. It is approximately 12 feet x 15 feet. I do have a basement but the patio is not over top of the basement. This house/patio is about 25 years old and I am in Pennsylvania (which means colder winters, snow, ice). Since there is nothing directly underneath and it is 6 feet from the house and since it is sagging in the middle, I would suspect there is a just dirt underneath.

There is a low point in the patio that causes water to puddle when it rains. This low point is just about the dead center of the slab which puts it about 6 feet from my house.

I had a concrete guy come out and he suggest I either (a.) rip out the pad and put in a new one, or (b.) put a new pad over top of the existing pad. I've been waiting on a price from him for the last month. In the meantime, I've looked online and some people have said they simply drilled a hole in the slab to let it drain down.

Now I don't know much about home building or engineering but I am thinking it would be a cheap and easy fix. The downside would be that the concrete might crack further (there is a hairline crack already) and I might have to replace the slab altogether after a few years. (But if I need to change the pad anyway, why not try drilling the hold first?!)

Thoughts? Could I do damage to my house/foundation by doing this? Any other thoughts?

p.s. I did read where somebody put a polymer sealant to deal with their concrete issue. The low point is probably 1/2 of an inch lower than the rest of the slab so I think it may be too deep.

It's probably settling because the soil underneath it wasn't compacted properly when it was installed. Drilling a hole and introducing water to the soil can actually make it worse. The real solution is to rip it out, fix the soil underneath and put a new slab on it. You could try some kind of leveling material over top of it to buy you some more time.

 

[83wuzme]

We had a similar problem due to a poor job to begin with by the contractor. In our case, the patio was at ground level. We had something called “ mud - jacking “ ( yes, I know there will be snickers about this term ) performed which lifted the side of the patio next to the house to facilitate drainage. They basically drilled a series of holes in the concrete and injected what appeared to be expanding foam that lifted one side up about 2 “.
I guess this won’t work for you if there isn’t dirt directly under the patio.
Maybe get rid of the patio and put in a deck ? $$$, I know.

 

[Langmuir]

Is it possible to put pavers or flagstone on top and level it that way?

 

[PearlSUJam]

One option that looks great is laying Pennsylvania blue stone/flagstone in mortar on top of the concrete. If laid correctly it could be pitched in any direction for run off.

 

[psuro]

I've got a raised concrete slab patio that is about 3 feet off the ground sitting on brick exterior and I'd guess the thickness of the pad is about 5 inches. It is adjacent to my house. It is approximately 12 feet x 15 feet. I do have a basement but the patio is not over top of the basement. This house/patio is about 25 years old and I am in Pennsylvania (which means colder winters, snow, ice). Since there is nothing directly underneath and it is 6 feet from the house and since it is sagging in the middle, I would suspect there is a just dirt underneath.

There is a low point in the patio that causes water to puddle when it rains. This low point is just about the dead center of the slab which puts it about 6 feet from my house.

I had a concrete guy come out and he suggest I either (a.) rip out the pad and put in a new one, or (b.) put a new pad over top of the existing pad. I've been waiting on a price from him for the last month. In the meantime, I've looked online and some people have said they simply drilled a hole in the slab to let it drain down.

Now I don't know much about home building or engineering but I am thinking it would be a cheap and easy fix. The downside would be that the concrete might crack further (there is a hairline crack already) and I might have to replace the slab altogether after a few years. (But if I need to change the pad anyway, why not try drilling the hold first?!)

Thoughts? Could I do damage to my house/foundation by doing this? Any other thoughts?

p.s. I did read where somebody put a polymer sealant to deal with their concrete issue. The low point is probably 1/2 of an inch lower than the rest of the slab so I think it may be too deep.

If you drill a hole to drain water, it will potentially get worse - the water will erode the underlying soil.

If it is raised 3 feet off the ground, and on a brick exterior, chances are you are also getting cold air underneath, which envelopes the concrete - this is what happens around bridges (and why you see a sign that says "Bridge freezes before roadway") - this will accelerate any cracking or eroding process underneath the concrete.

If you want peace of mind, and you want to have the patio 3 feet above grade, consider

1. Removing the whole thing and replacing with a pressurized wood raised patio.
2. Remove the whole thing, inspect it and resolve any holes/channels, etc that need to be repaired.

If you don't want a raised patio, then consider removing the whole thing and pouring a slab on grade concrete patio.

.

 

[PearlSUJam]

Is it possible to put pavers or flagstone on top and level it that way?

Beat me to it. I've done many jobs like this with flagstone.

 

[MJG-90]

I’m confused. Is it connected to the house? Or six feet from the house? Is there nothing underneath or dirt underneath?

If it is boxed in it should have had fill under it. I don’t care how much you pack it, it will still settle over time. If the surface is in otherwise good condition, try the suggestion above — get it drilled and filled. I’ve seen this done with sidewalks many times. Looks fine. Barely notice where the holes were drilled.

 

[Langmuir]

Beat me to it. I've done many jobs like this with flagstone.

I built my own flagstone patio set in mortar over 10 years ago. It needs some work now but held up pretty good considering I did not do a great job of leveling and grading the stones for water run off. It is on the north side of the house and gets very little sun in the winter and always has moss growing in the mortar in the summer. I need to chip out the disintegrated grout and reset a few of the stones. I am not looking forward to the job but it needs to get done, maybe when it gets a little cooler.

 

[PearlSUJam]

I built my own flagstone patio set in mortar over 10 years ago. It needs some work now but held up pretty good considering I did not do a great job of leveling and grading the stones for water run off. It is on the north side of the house and gets very little sun in the winter and always has moss growing in the mortar in the summer. I need to chip out the disintegrated grout and reset a few of the stones. I am not looking forward to the job but it needs to get done, maybe when it gets a little cooler.

I really like the look of the random cut style.

http://www.bourgetbros.com/product/bluestone-random-pattern-pavers/

 

[sluggo72]

We had a similar problem due to a poor job to begin with by the contractor. In our case, the patio was at ground level. We had something called “ mud - jacking “ ( yes, I know there will be snickers about this term ) performed which lifted the side of the patio next to the house to facilitate drainage. They basically drilled a series of holes in the concrete and injected what appeared to be expanding foam that lifted one side up about 2 “.
I guess this won’t work for you if there isn’t dirt directly under the patio.
Maybe get rid of the patio and put in a deck ? $$$, I know.

this^^^^^ some call it concrete leveling, I've had it done. They drill a hole, and pump 'stuff' into until the concrete pops up to a level position. A lot cheaper than a tear out and replace.

 

[fastlax16]

My jury rigged solution would be to cut a groove/channel that allows water to drain off the edge instead.

 

[Langmuir]

I really like the look of the random cut style.

http://www.bourgetbros.com/product/bluestone-random-pattern-pavers/

Mine is very random and not as tight as I would like. I used something like this

https://stakerparson.com/landscape/...tes/6/2014/12/Blue-Stone-Standup-768x1024.jpg

The stones are big.

 

[Pardlion]

I've got a raised concrete slab patio that is about 3 feet off the ground sitting on brick exterior and I'd guess the thickness of the pad is about 5 inches. It is adjacent to my house. It is approximately 12 feet x 15 feet. I do have a basement but the patio is not over top of the basement. This house/patio is about 25 years old and I am in Pennsylvania (which means colder winters, snow, ice). Since there is nothing directly underneath and it is 6 feet from the house and since it is sagging in the middle, I would suspect there is a just dirt underneath.

There is a low point in the patio that causes water to puddle when it rains. This low point is just about the dead center of the slab which puts it about 6 feet from my house.

I had a concrete guy come out and he suggest I either (a.) rip out the pad and put in a new one, or (b.) put a new pad over top of the existing pad. I've been waiting on a price from him for the last month. In the meantime, I've looked online and some people have said they simply drilled a hole in the slab to let it drain down.

Now I don't know much about home building or engineering but I am thinking it would be a cheap and easy fix. The downside would be that the concrete might crack further (there is a hairline crack already) and I might have to replace the slab altogether after a few years. (But if I need to change the pad anyway, why not try drilling the hold first?!)

Thoughts? Could I do damage to my house/foundation by doing this? Any other thoughts?

p.s. I did read where somebody put a polymer sealant to deal with their concrete issue. The low point is probably 1/2 of an inch lower than the rest of the slab so I think it may be too deep.

Just set up your furniture around the low spot and use it as a fire pit.

 

[nitanee123]

One option that looks great is laying Pennsylvania blue stone/flagstone in mortar on top of the concrete. If laid correctly it could be pitched in any direction for run off.

Pearl - Stupid question. Who would I call to do such a job? Is it landscaping?

 

[PearlSUJam]

Mine is very random and not as tight as I would like. I used something like this

https://stakerparson.com/landscape/...tes/6/2014/12/Blue-Stone-Standup-768x1024.jpg

The stones are big.

Those kind are the reason I don't do masonry work anymore.

 

[nitanee123]

If you drill a hole to drain water, it will potentially get worse - the water will erode the underlying soil.

If it is raised 3 feet off the ground, and on a brick exterior, chances are you are also getting cold air underneath, which envelopes the concrete - this is what happens around bridges (and why you see a sign that says "Bridge freezes before roadway") - this will accelerate any cracking or eroding process underneath the concrete.

If you want peace of mind, and you want to have the patio 3 feet above grade, consider

1. Removing the whole thing and replacing with a pressurized wood raised patio.
2. Remove the whole thing, inspect it and resolve any holes/channels, etc that need to be repaired.

If you don't want a raised patio, then consider removing the whole thing and pouring a slab on grade concrete patio.

.

Ro - What do you think of the pavers/bluestone idea? I hate to remove the whole thing if I can avoid it.

 

[psuro]

Ro - What do you think of the pavers/bluestone idea? I hate to remove the whole thing if I can avoid it.

I think it will keep rain from getting the top, but unless you explore what is going on underneath the top surface, you may only be putting bandaid on a broken bone.

 

[PearlSUJam]

Pearl - Stupid question. Who would I call to do such a job? Is it landscaping?

Not stupid at all. I'd talk to some trusted masonry contractors in your area.

Has the puddling been happening all along or is it a recent problem?

 

[cvilleelkscoach]

this^^^^^ some call it concrete leveling, I've had it done. They drill a hole, and pump 'stuff' into until the concrete pops up to a level position. A lot cheaper than a tear out and replace.

I would recommend this slab jacking solution too. Much less than ripping it all out

 

[nitanee123]

Not stupid at all. I'd talk to some trusted masonry contractors in your area.

Has the puddling been happening all along or is it a recent problem?

I purchased the house about 5 years ago and it has been puddling since at least that time.

 

[nitanee123]

I would recommend this slab jacking solution too. Much less than ripping it all out

Unfortunately I don't know if its dirt or air underneath. If its air, I wouldn't think jacking it up would make sense.

 

[PearlSUJam]

I purchased the house about 5 years ago and it has been puddling since at least that time.

I'm assuming it's probably back filled with gravel or dirt. It's possible that it was poured like that from the start. I have a similar situation at work and it began with the first rain storm after the contractors left. Concrete won't sag without substantial cracking. Are there any relief joints cut or is it one complete pad?

 

[sluggo72]

Unfortunately I don't know if its dirt or air underneath. If its air, I wouldn't think jacking it up would make sense.

makes absolute sense. The stuff they pump in fills the void that has been caused, most likely from water eroding underneath. It is some sort of aggregate

 

[nitanee123]

I'm assuming it's probably back filled with gravel or dirt. It's possible that it was poured like that from the start. I have a similar situation at work and it began with the first rain storm after the contractors left. Concrete won't sag without substantial cracking. Are there any relief joints cut or is it one complete pad?

Well the entire pad is approx 12 x 25 (300 square feet) and is divided by a relief joint. My issue is with one of the sides (12 x 15 ).

 

[nitanee123]

makes absolute sense. The stuff they pump in fills the void that has been caused, most likely from water eroding underneath. It is some sort of aggregate

If the entire pad is 300 square feet and its 3 feet above, we are talking about possibly 900 cubic feet of material. I don't know exactly how the stuff works but my initial thought seems like it wouldn't apply.

I just called a mason and he is going to call me back later today. I'll ask him if this is an option.

 

[WDLion]

I'm assuming it's probably back filled with gravel or dirt. It's possible that it was poured like that from the start. I have a similar situation at work and it began with the first rain storm after the contractors left. Concrete won't sag without substantial cracking. Are there any relief joints cut or is it one complete pad?

It probably sagged in the center before the concrete completely hardened. 5" of hard concrete will not sag in the center.

 

[SLUPSU]

If the entire pad is 300 square feet and its 3 feet above, we are talking about possibly 900 cubic feet of material. I don't know exactly how the stuff works but my initial thought seems like it wouldn't apply.

I just called a mason and he is going to call me back later today. I'll ask him if this is an option.

I can't imagine a reason why this slab would be elevated three feet with nothing under it, perhaps this area was attached to the house in the past. Assuming this slab is close to the house is it possible it was part of the basement at some point in the past? In that scenario, mud-jacking would be prohibitively expensive. If the slab was poured over loose gravel, then mud-jacking process would require more "mud" than usual and drive the cost up also. If mud-jacking doesn't work out, then covering the area with a colored pavers after drilling more holes to "improve" the drainage is another option to look into, that's also not a difficult DIY fix.

 

[WDLion]

I can't imagine a reason why this slab would be elevated three feet with nothing under it, perhaps this area was attached to the house in the past. Assuming this slab is close to the house is it possible it was part of the basement at some point in the past? In that scenario, mud-jacking would be prohibitively expensive. If the slab was poured over loose gravel, then mud-jacking process would require more "mud" than usual and drive the cost up also. If mud-jacking doesn't work out, then covering the area with a colored pavers after drilling more holes to "improve" the drainage is another option to look into, that's also not a difficult DIY fix.

I can't imagine a reason why this slab would be elevated three feet with nothing under it
It's levitating.

 

[PearlSUJam]

I can't imagine a reason why this slab would be elevated three feet with nothing under it
It's levitating.

Often times metal panning is used like on bridges, but dirt is usually cheaper depending where building.

 

[SLUPSU]

Often times metal panning is used like on bridges, but dirt is usually cheaper depending where building.

Metal decking is rarely ever used typical residential construction, (I suppose it could be used for a small tornado shelter) in this case it could not span 15' without adding steel beams, even more unlikely for a patio slab.

 

[PearlSUJam]

Metal decking is rarely ever used typical residential construction, (I suppose it could be used for a small tornado shelter) in this case it could not span 15' without adding steel beams, even more unlikely for a patio slab.

I've used it plenty of times in residential. If the homeowner wants basement space below their front porch that is concrete, decking is used. I agree it is unlikely, but I've seen much crazier things done while demo-ing these types of projects. In a post above I said it's most likely filled with gravel or dirt. I was just explaining the levitating aspect of another post.

 

[SLUPSU]

I've used it plenty of times in residential. If the homeowner wants basement space below their front porch that is concrete, decking is used.

That's just like the tornado shelter example, used as a temp concrete form/shoring not as a structural element.

 

[PearlSUJam]

That's just like the tornado shelter example, used as a temp concrete form/shoring not as a structural element.

You mean wine cellar, right? That's what the engineers had drawn up on the prints. Along with plenty of tied rebar.

 

[cjflyfish]

It's probably settling because the soil underneath it wasn't compacted properly when it was installed. Drilling a hole and introducing water to the soil can actually make it worse. The real solution is to rip it out, fix the soil underneath and put a new slab on it. You could try some kind of leveling material over top of it to buy you some more time.

^This

 

[step.eng69]

If the entire pad is 300 square feet and its 3 feet above, we are talking about possibly 900 cubic feet of material. I don't know exactly how the stuff works but my initial thought seems like it wouldn't apply.

I just called a mason and he is going to call me back later today. I'll ask him if this is an option.

It is not physically possible to have a concrete slab w/wire fabric reinforcement span 12' or 25'. It couldn't support it's own weight, let alone any type of live loading. It couldn't be constructed. It would collapse while placing the concrete. I can guarantee the slab is supported by compacted soil and possibly 4"-6" depth of ASHTO #57 aggregate or 2B (3/4") aggregate between the soil and bottom of slab.

Typically during the heave & settlement of the slab during the seasons, the support soil material can displace over time and produce a void in the underlying soil support. Also, if your soil profile for the area contains substantial clay, loam, silt...the soil may have moderate expansive capability depending on varying, moisture content...meaning it will expand and shrink with higher moisture and lower moisture.

I would believe the above and some water seepage from the house/deck expansion filler joint connection is migrating under the slab or possibly one side of the raised slab has the yard graded (sloped) into the 3' wall where it should be sloped away.
The grading issue causes major problems with houses in time.

Poly-foam-jacking or mud-jacking would be the least expensive way to raise the slab. Look for a contractor that does both. depending, on the issues (voids) one of the methods will be the better value.

 

[soulkitchen74]

My jury rigged solution would be to cut a groove/channel that allows water to drain off the edge instead.

This. I did this in a driveway. Worked well and it doesn't need to be a large groove. Go from the center low spot out.