DIY Fiberglass Pool

[scottmcwms]

I am considering building my own fiberglass pool. I don't mean buying a shell and dropping it in the ground DIY style. I'm considering building a concrete shell and then hiring a company to line it with fiberglass. This would allow me to customize the pool to the exact dimensions and configuration we want. I'm looking for some feedback on my thoughts and also looking to see if anyone has done something like this before.

I don't like the idea of a concrete pool. I've never liked plaster. I don't like the maintenance, chemistry and replastering cost. Also concrete pools in this area (NW Houston) have a lot of cracking issues due to high-heave clay soil. I'm not opposed to concrete, but I feel like there may be a better option.

I don't have $100k to spend on a pool so I am looking to DIY as much as I can. I live in one of those neighborhoods where you have to get approval to buy a new pair of shoes so I'm pretty sure a vinyl liner pool is out of the question. I need to go with a concrete or fiberglass design that would reflect pools in the neighborhood. I could go with a fiberglass shell, but it would cost $7,000 for the crane and permits to lift the shell off the truck and drop it in my backyard. Small lots and high roof lines close to the street create the need for a really large crane to reach over the house and I'm pretty sure our street is too narrow to facilitate such a crane. So I am limited to a concrete pool, but a concrete pool isn't very DIY friendly. When I say DIY I don't mean I would be the GC. I'm talking about me doing the work myself.

So after watching at least 100 videos online including the Nicole Michael DIY pool and several fiberglass pond installations in the UK I started wondering if I could combine the two and have a really solid pool. My initial design thoughts are to

• dig the hole (DIY friendly)
• lay rebar (DIY friendly)
• pour an appropriate slab (contracted due to concrete volume)
• build a concrete block wall, steps and spa (see screenshot of overhead view) utilizing rebar integrated into the slab (DIY friendly)
• run piping and electrical to lights, suction, returns and backwash discharge (DIY friendly)
• fill concrete block holes with grout and rebar (DIY friendly)
• lay fiberglass over concrete blocks and concrete slab to create a solid surface (contracted to ensure quality). Gelcoat fiberglass to the exact color we want.
• install pump, filter and heater (DIY friendly)

I know there are a bunch of other steps in there that I didn't include and I also understand that I should gunite instead of pouring a slab and doing a concrete block wall, but the gunite contractors around here have insane pricing. In my mind I can do most of this work myself (I'm very handy) thus saving a ton of money. The cast in place fiberglass shell would eliminate most of the risk of any concrete block wall movement creating cracks. This process is done very frequently in the UK on a much smaller scale for fiberglass ponds (think koi fish ponds) but I've never seen it done for a swimming pool. I'm trying to see if anyone has done something like this before and if I am completely crazy for dreaming this up. This seems like a really good way to have a pool with a much lower entry cost.

Feel free to shoot holes in my idea. I'm testing viability.

 

[ajw22]

Finding a contractor to pour concrete should be easy.

Before you invest to much energy in this plan see if you can find some contractors to do the fiberglass work. Best place to look is boat builders. You may find the folks who can do fiberglass work have no interest in doing it in a residential pool.

I think finding a fiberglass contractor who you like may be the obstacle in your plan.

 

[scottmcwms]

Finding a contractor to pour concrete should be easy.

Before you invest to much energy in this plan see if you can find some contractors to do the fiberglass work. Best place to look is boat builders. You may find the folks who can do fiberglass work have no interest in doing it in a residential pool.

I think finding a fiberglass contractor who you like may be the obstacle in your plan.

Good point. After a quick search there is at least one contractor in this area that will line a concrete pool with fiberglass. They call it concrete pool resurfacing. But I will definitely do my diligence on the process.

 

[ajw22]

Talk to them about what structure and surface prep they need to do their installation.

 

[newdude]

After a quick search there is at least one contractor in this area that will line a concrete pool with fiberglass.

They might not with a cinderblock pool.

 

[kimkats]

Finding the SKILLED labor to do the fiberglass is going to be your biggest stumbling block is my guess also.

 

[sktn77a]

I googled fiberglass pool resurfacers several years back (pre-covid) - none of them responded!

 

[keithw]

I would be concerned about the possibility of water getting between the fiberglass and the cement shell.

 

[.ben]

Interesting idea. I’m interested in reading along if you proceed. However…

Does your city/county or HOA require structural engineering plans as part of the approval?

You may have difficulty finding an engineer to design per your specific specifications. CMU block pools are not the norm in this area.

Are you ever going to sell your property? You may be okay assuming the risk of failure (structural or otherwise) of your novel pool, but the next owner may not. Maybe they won’t care.

 

[scottmcwms]

Good points from everyone. I appreciate everyone challenging the design. It helps me think through what needs to be considered.

I have contacted a few resurfacers and they are onboard with the plan. I have asked for references. That should be a good indicator of if they are valid or not.

I too was concerned about water getting between the fiberglass and the concrete blocks, but since concrete is porous I don't see how it will act any different than the gunite shell of a plaster pool. Through the process of osmosis it should migrate from higher concentration in that location to the external surface of the blocks and the rock backfill material. Also that is why I want a pro to install the fiberglass. Fiberglass is impermeable to water if properly installed. That is why boats that sit in water don't take on water over time unless they are cheap or cracked. Cheap fiberglass that isn't fully impregnated with resin can be porous. With three layers of mat and resin it should be good.

I don't live in a city but I do live in a master planned community (township) that has an architectural review committee. Their charter is to enforce the architectural standards of the community and ensure any improvements meet the "look" of the community. They are way more concerned about aesthetics than anything else! Technically they have zero authority to enforce engineering design requirements above what the county requires, but they can make your life miserable until you give up! For example, I recently added a cover to my back patio. It was integrated into the house siding with flashing and shingles. I was required to make it look like it was original construction which was easy. The county requires any covered structure over 200 sq. ft. to have drawings stamped by an engineer. The committee can enforce that requirement but they couldn't say their requirement is anything over 180 sq. ft. Regarding pools, the county only requires engineered pool design plans if the pool would be in a 100-year floodplain, which it won't. If you think about it I am designing a concrete block retaining wall similar to the ones you see all over the place, except the difference is that there are forces acting on both sides of the wall instead of just one side. It is actually a much simpler problem to solve. Being an engineer myself I am confident in my ability to design the walls and slab although I can't stamp my own drawings. So the review committee will receive engineered drawings (which are not required). Also I bet there are very few pool companies that actually engineer their pools which is why many of them crack.

I have thought about the resale implications. I talked to a home inspector that also does pre-purchase pool inspections. He said that they are only required to assess the apparent structural condition of the pool (cracks, out of level, bulging, plaster condition, deck shifting, etc.), stains, fading, pump/heater/filter and visible piping condition to note any visible concerns about the structural integrity or the functionality of the pool. They don't review drawings or dig into the build of the pool because (1) they aren't required to, and (2) most of the time that info isn't available. I don't intend to be deceptive because I fully expect this pool to be as good as if not better than a $100k "professional" pool, but when I go to sell the house if the pool doesn't have any problems then why would I disclose how the pool was built? Also if it has problems in the future it would be very easy to repair the fiberglass or just backfill it.

Keep the challenges coming!

 

[sktn77a]

Also if it has problems in the future it would be very easy to............................... just backfill it.

If only that were true!

A permit and inspection record is usually all that's needed (for better or for worse). Banks sometimes want them as part of the appraisal and insurance companies sometimes want them for new policy risk assessment).