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How to renovate a cracked concrete swimming pool?

Hi everyone,

I’m hoping to get some advice on the best way to fix my pool.

We moved into our home about 20 years ago, and I was told the pool is made of Besser blocks with concrete and some fiberglass patches, which were then painted over.

Unfortunately, it hasn’t been repainted in a long time, and when I recently drained it to prep for either - repainting, adding a vinyl liner, or tiling, I discovered a large crack at the bottom.

I plan to do a lot of the prep work myself—sandblasting the sides, grinding if needed, and making sure everything is smooth and ready.

As a single mum on a mortgage with a limited budget, I’d love to hear your recommendations on the best, most cost-effective way to repair the pool,

so, it looks good and stays functional. Any advice would be greatly appreciated!

Thanks in advance!

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Tools and Materials

Repairing

Tiling

Pools and Spas

Comments

EricL

Hello @Avsvs

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your swimming pool.

It's good to hear that you are ready to tackle all the prep-work that's required to get your pool functional again. If there is one part where I suggest spending money on, it is on the repair of the crack in the pool. I recommend engaging the services of a professional pool restoration specialist, they should be able to determine if the foundation of the pool has been compromised or if the crack at the bottom can simply be sealed. Spending your budget on the best possible seal you can find means that you' won't have to worry about water draining out for years.

I also recommend having the pool pump checked out while you are having your pool damage analysed. I suspect that a new pool filter will at least be in the list of things that need to be changed, and I just want you to be prepared for certain parts of the pump system to be replaced, especially if it has been left outside for quite a while.

Once the main issues have been addressed, the last thing you want to make sure is that your pool fence is complaint. Is the magnetic lock still working, is the height of the fence still passing regulation are any of the posts rusting and needing replacement? I also recommend checking the rules and regulations of your local council in regards to pool fencing and accessibility.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let us know.

Eric

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/48700#Comment_48700

Good Evening @Avsvs

Woooooo as I am reading your job list 🙂

I would definently spend a chunk of money and get the crack and base structure checked by a pool professional (one with abn and has references you can look at) They will also be able to tell you the things that you can do and shouldnt do repair wise. I had a mate who had his fibreglass pool surface repaired and it was a headache. I have a fibreglass pool that is old and probarly needs resurfacing and has cracks on the coping but its still going ok. Its on my list of things to repair one day.

Your pool walls look in resonable condition tho the concrete fill on the steps will need to be sealed, I would talk to the person you get to investigate that crack for suggestions on handling that.

If you have a sand filter, they are resonably easy to replace the sand. I actually bought a new replacement and watch the pool guy install it (I removed all the old sand from the old filter before he arrived to make the job cheaper lol) I kicked myself I didnt have the confidence as it was almost a reversal of removing the sand. I could probarly kept on using the same sand filter but with fresh sand (The sand does degrade and should be replaced every 10 years ish)

Is the pool a salt water or chlorine based pool?

I do think its a really nice project to follow through and also think that you could do a bunch of stuff yourself (or even just use you for labour) while the work is being done to fix that crack. Do you remember the pool loosing water before it was emptied? Looking forward to this project 🙂

Dave

Avsvs

https://www.workshop.bunnings.com.au/discussion/comment/86433#Comment_86433

Hi Dave

Thanks for your response.

No the pool never lost water and that crack was filled with silicon and then I think they put a thin layer of fibre glass over the top.

I have had a few pool guys come out and quoted all over the 40's which is well out of my budget. I am fairly handy and will try and do prep etc myself. Spoke to one pool guy today and he suggested cleaning to smooth surface and tiling which I could probably do slowly over winter. Other option is to clean and prep all surfaces and then get a good thick vinyl inlay which seem to be quite popular. Have to do a bit more research.

Yes have a sand filter and have changed sand previously so that's all good. Just don't know where to start. Was thinking blast it all first with water jet get as much paint and gunk off then grind and then sand blast. The crack at the bottom will be treated same way and then thinking to grind out and put that concrete stuff they use for concrete water tanks and then would have liner or tiles over . Also need to change direction of water outlet as not getting enough movement in pool. First had chlorine and then got a salt filter now just green swamp. Thanks for your response any other tips advise would be great as I am very new to all this. Other thing I was thinking doni just render over the whole lot. Would that work 🤔

Cheers Andrea

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/108580#Comment_108580

Evening @Avsvs

Excited that the pool dosnt leak!

Like really, really maybe win the lotto time type deal.

Id be tempted to actually fill the pool by a third and mark the water level on the side as is (get rid of loose dirt ect first tho) Allow for evaporation or better yet test overnight and see if it drops. If it dosnt then no way would I be disturbing what has been used on thatcrack! 😀

I say a third to give a resonable weight to the water to push the limits of the sealed crack.

If it passes that test then it may be worthwhile looking into a pool paint sealer. Depending on what your surface is like I would be cautios of a super powerful water jet. Ive never changed the water jet outlets tho need to. When I do I will be taking a photo of the jet nosel into a pool place and asking if they have the same and then kindly ask them how to remove them 🙂 I am hoping that the jet is front facing so they can be popped/levered out and then a new one put in.

Dave

I did think of a liner and that is def in the ballpark if the pool is notleaking. It would bring it up very nicely.

Tiling would make the edge smooth yes but it dosnt waterproof. Plus I have had to clean a tiled pool top edge... Id rather the old firberglass pool I have 🙂

Dave

Avsvs

https://www.workshop.bunnings.com.au/discussion/comment/48700#Comment_48700

Hi Eric

Thanks for your message.

Yes hoping to do alot of prep work myself. Yes I would like to get a pool restoration expert re the crack which has been there for a long time it is only more noticeable as I took off the fibreglass which was over the top.

Yes have new pool fence to go around and also extend out to give more room around pool. I am excited 😊 to get this underway just not sure.where or how to start 😄

Jason

https://www.workshop.bunnings.com.au/discussion/comment/86437#Comment_86437

Hi @Avsvs,

Let me tag @2Belindas to see if she can join in the discussion. You can see her pool renovation project here - Pool before and after.

@JRRed has also completed pool restoration work and might like to add their thoughts.

Jason

Avsvs

Hi guys so I am still going. Have had pool sandblasted not quite finished and have found some doozie cracks under fibreglass. So plan is to fill and then paint whole pool with few coats of epoxy pool paint. Thoughts? Ideas for cracks

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/51728#Comment_51728

Good Evening @Avsvs

That crack is pretty large, does it line up with the crack on the bottom of the pool or with a crack on the oppisite side? I have concerns that structually it may have issues and would be at the point of getting an engineer to have a look/survey to make sure you arnt starring in the "Money pit" (Great Movie but you get the drift)

I have not used an "epoxy pool paint" before but even with a few coats I am still concerned that crack will continue to open up, I would be thinking of stabilising the structure first (making sure the side of the pool isnt sinking either end therefore opening up the crack) So would strongly suggest to get a proffesional to have a look.

Dave

EricL

https://www.workshop.bunnings.com.au/discussion/comment/51728#Comment_51728

Hello @Avsvs

I definitely agree with @Dave-1 in his assessment. I strongly suggest having a pool specialist come over and have a look at those concrete fissures to make sure that your pool is still viable.

Eric

Avsvs

https://www.workshop.bunnings.com.au/discussion/comment/88007#Comment_88007

Hi Dave,

Unfortunately i can not afford to get an engineer out - just isn't an option, however this is what i have found

High-pressure injection of epoxy or polyurethane resins is used to repair deep cracks in concrete. Polyurethane is typically used for active or live cracks, while epoxy is preferred for dormant cracks or when structural integrity is the primary concern. Polyurethane, with its expanding properties, excels in sealing wet and moving cracks, whereas epoxy offers high strength and permanence when structural integrity is crucial.
Epoxy Injection:
- Application:
  
  Suitable for dry, dormant cracks or where structural repair and strength are paramount.
- Mechanism:
  
  A low-viscosity epoxy resin is injected under pressure to fill the crack, restoring structural integrity and reducing water penetration.
- Pressure:
  
  Typically performed at lower injection pressures (20-200 psi).
- Limitations:
  
  May not be suitable for active cracks or when future movement is anticipated.
Polyurethane Injection:
- Application:
  
  Ideal for wet, leaking cracks and cracks subject to movement.
- Mechanism:
  
  A water-reactive polyurethane resin is injected under pressure. The resin expands upon contact with water, sealing the crack and preventing further leakage.
- Pressure:
  
  Often performed at higher pressures to ensure the expanding foam fills the entire crack.
- Advantages:
  
  Flexible and durable, can adapt to crack movement, and is suitable for various crack widths.
Choosing between Epoxy and Polyurethane:

The choice depends on the nature of the crack, the presence of water, and the desired outcome.
- Structural Repair:
  
  Epoxy is preferred for cracks that compromise the structural integrity of the concrete.
- Water Leakage:
  
  Polyurethane is excellent for sealing wet and leaking cracks, as it reacts with water to form a watertight seal.
- Cracks Subject to Movement:
  
  Polyurethane's flexibility makes it suitable for cracks that may experience movement.

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/109625#Comment_109625

Afternoon @Avsvs

I feel your pain, really do (My old school fibreglass pool has a cracked cowl and other things associated with age) and I will be in that same problem area one day as well.

So lets narrow the issue down, Cant afford an Engineer (neither could I short term) tick

Willing to give it a go, tick

Have researched potential ways to fill the crack, tick

Use a paint sealer once crack is filled, kinda tick 🙂

Fill with water and see, waiting for that tick.

Two things come to mind as I go through the steps.

1 - Low side of your pool structure, if it fails where will the water go and what damage could it do? My pool is a 45,000L pool and I often think about "what ifs" 🙂

2 - Using a rubber liner for the pool itself. So crack is fixed/filled with something flexible enough to last a few years. And then a rubber liner much like an above ground pool is used instead of a painted surface so other cracks may be less of an issue.

I take small steps to solve big problems, its scary spending $$$$ on a repair that may not work but if you havenothing to loose I would say why not. (apart from physical danger of where that water may end up of course and oif you were in the pool at that point of time and failure) Kinda have to say that as it would be remiss of me not not just in case 🙂

Looking forward to seeing your steps 🙂

Dave

MitchellMc

Hi @Avsvs,

With structural cracks to this degree, I think you'll find that most pool restoration experts would determine that the base is unstable and the shell is too damaged to repair. They'd want to remove it and start from scratch. These aren't fine cracks, they are structural and show that the shell is essentially falling apart due to the ground moving beneath it. They might perform a repair and fill the cracks, but it would likely not come with a warranty.

Wanting to do the work is admirable, but I just wanted to point out that it's so damaged you'd likely find it difficult to even enlist the services of a professional to repair it. I have a much finer single crack in the bottom of my pool, and even that has been deemed as non-repairable.

Have you considered the prospect of filling the pool in? That obviously might not suit you, but for me it would certainly be an option. Mine is currently unusable and taking up a large portion of the yard, which my children use to play in.

If you still want to go ahead, then I would suggest getting some quotes on the repair. Even if you don't go ahead with them, they'd give you a good idea of what needs to be done in order to stabilise the moving shell and repair the damage to it.

Mitchell

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/51753#Comment_51753

Afternoon @Avsvs

As a side note, I have often wondered what to do with an empty pool, With yours the sides seem stable (not wanting to falling inwards) Mine is a fibreglass pool so if I empty it, the sides will collapse inwards most likely.

The hole in the ground is a perfect cooler area, especially with a roof covering of some kind. maybe convert your pool shell to something like a sunken gazebo until you decide what you can do? A few short posts along the edge of the pool, a couple of wires and you could string up a shade sail that you could retract? Gives you something to have while you sort out the issue.

Dave

Avsvs

https://www.workshop.bunnings.com.au/discussion/comment/88007#Comment_88007

Hi Dave and everyone,

I’m not sure how to reply to all, so I hope this reaches the right people.

I just remembered that my brother in Melbourne is a structural engineer. I’ve sent him some photos, and he will most likely fly over to take a look in person.

I also work at Modbury Hospital with the team managing the current new builds. I’ve been asking the builders lots of questions—probably driving them crazy! They’ve even started asking their own contacts for advice, so I’m confident we’ll find a good solution.

I’ll put together a list of different repair options I’ve researched and share it soon so we can see what the general consensus is.

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/109640#Comment_109640

Afternoon @Avsvs

🙂 I think thats the way we all learn, I always figure "there is no harm asking" as even a non positive answer still leads teh way forwatrd 🙂

Definently handy having family you can hit up 🙂

My back up crew is the workshop crew where I work and also the IT crew for IT related questions 🙂

Looking forward to hearing ideas.

Dave

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