New deck heaving


LifeTime Supporter
Aug 1, 2013
Cypress, TX
Hydraulic expansion is my guess as well. I'm in SE Texas with a pool built in/after drought conditions-2012. My pool deck did the same thing after about 6 months at the union to the existing patio (even with re-bar tie-in). My PB came back and redid a 16-inch swath around the entire patio. Not an easy task, but we didn't feel the deck would correct itself. It's holding firm after 6 months.
I think I just found the answer to my question in my build thread about decking...

Pragmatic, is there any way to prevent this? So this is a common occurrence for concrete decking in TX? I can see this being a major tripping hazard later. Thanks for posting this info.


Active member
May 28, 2013
Have new mastic going down but deck heave has worsened (grown to 18ft in length). Still working with PB who says its just ground swell and nothing they did wrong. No leaks via bucket tests.
While I agree our ground swells its now begun its shrinking as I notice my front walk now going down from its winter evenness which leads to believe that the deck should have also started going down if its just swell.
PB suggests I get an engineer out (major cost) to look it over and provide suggestions.
Thoughts/suggestions from this forum?


TFP Expert
Apr 19, 2013
Sacramento, CA
I'm going to suggest you follow the PB lead and get a soils engineer out there to look at it. Call around some can be less expensive than others. Something is causing that heaving and its going on over time so I would have an engineer look at it. It may be lees expensive than you think. And it may prevent more damage down the road.

Do you have any close neighbors with pools that could be leaking?


Well-known member
Jan 25, 2013
The Great State of Texas
I looked at having a lot of poured surface put in around an existing pool. A friend of the family who pours commercially (so no dog in my fight) told me not to pour any surface in this area until the drought was over. Said it was just asking for trouble. When I had my pool facelift done a few months ago the sales guy told me smartest thing I did was to sod around the pool. He said everything that was being poured was cracking.

Probably not a great answer. Sorry.


Active member
Mar 26, 2014
Mesquite, Texas
I live in Mesquite. We had an original pool built in 1993. No problems. 18 years later, the back deck started to heave in one area. It was related to the extensive drought and the clay soil contracting. We've had a lot of rain the past couple of weeks but this winter really was abnormally dry and just added on to the four, going on five, year drought.


LifeTime Supporter
Jul 7, 2011
Friendswood, TX
I think I just found the answer to my question in my build thread about decking...

Pragmatic, is there any way to prevent this? So this is a common occurrence for concrete decking in TX? I can see this being a major tripping hazard later. Thanks for posting this info.
Hi CC,
Sorry for the delay in my reply. From what I've seen, it's very common with decking poured at different times/different ground conditions. I'm sure some things can be done to prevent it (at what expense is the question). The tripping hazard was my concern as well. I was lucky in the fact that mine was not so severe. More lucky that my PB agreed to tear out a swath and re-pour around the existing patio. Immediately after the PB finished the pour I sealed the expansion gap to prevent any water from seeping in. So far, so good-no cracking or lifting (going on about a year now). We'll see how it does after all the recent rainfall in our area. IMO, the best substrate for around our pools would be travertine pavers (rough finish) installed over stabilized sand; possibly over a concrete slab base.
I'll look for some b4 & after pics of my decking, but I can tell you it was not nearly as bad as the pictures (links you posted).

- - - Updated - - -

This is exactly what mine was doing!


Active member
May 28, 2013

Had the mastic redone (at my cost) but cracks are getting worse. PB owner is coming tomorrow to talk. Few questions i have for the PB. Anything i am missing?

heave is now so bad that rain water pushes toward my back door and stands there since it cant drain uphill. PB thinks this is magnifying the problem and wants me to spend money to add a drain in my old patio. I still want to know the cause of the heave.

1. What caused the heave?
2. if it was ground swell how did the water get under the deck? Did the mastic fail? Was it due to the 2wks (with a few rains) where the gutter wasn't tied in properly and water got under the deck?
3. Why are the cracks getting worse and multiplying?
4. The water line on the side where the deck is heaving is 1.5 cm lower than the water line at the other end of the pool. is this normal? could the whole pool be lifting?


Active member
May 28, 2013
Heaved portion of deck being torn up now. Never settled back down. Deck guy says he is going to compact the fill as best he can and that might keep it from heaving again. Also might tie it into my existing concrete patio.

Thoughts/suggestions on other things to do prior to pour? Saturate the fill? Extra rebar?


LifeTime Supporter
Just saw this thread for the first time. Wow man. So glad you got your PB to own up to this and fix it for you. <Whew> My deck was poured 9/8/14 and I still don't have mastic yet. After learning about "deck heaving" it scares me and I hope this does not happen to me.


LifeTime Supporter
Oct 9, 2009
Did you ever have an engineer look at it? Hopefully so since even the PB recommended it.

Things like this are complicated. No one can give you a good answer just based on the pics. The thing is if decking is being replaced somebody is laying out some major cash on this issue. However, it is sounds doubtful that the underlying issue is getting fixed. Perhaps it was fill settling and it won't happen again. But what if it is clay soil expansion? Compacting the fill won't prevent that from happening again


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
FL panhandle
The best time to lay pavers (or deck) is when the ground is wet and then keep it watered when it is dry. Much better than laying it dry and having the ground swell when it rains. You can put water in the ground but you can't take it out. Same as watering your house foundation during dry seasons. Maintaining consistent moisture level is the key.