Vermiculite is the usual choice of floor material for inground vinyl liner pools. it is not the cheapest option for your floor, but it is long lasting and one of the easier floor materials to install. This article covers the necessary steps and supplies for installing your own vermiculite and cement pool floor.
Where to Buy Pool VermiculiteFinding it locally in your area can sometimes be difficult. First, I would check with nearby hardware stores and also local pool dealers. Concrete supply stores and even commercial lawn and garden places. The easiest place to get the pool vermiculite you’ll need would be from SPP. We have 28 lb bags for about $1 per pound, with free shipping. Buy pool floor vermiculite at the time you purchase your pool, and it can be delivered along with the pool kit, or you can buy local, just make sure that you use coarse grade vermiculite for your pool floor - as shown in the image above. it is much easier to mix and work with than fine or medium grade vermiculite. Another option is to call the two largest manufacturers of the product to see where it can be purchased in your area, they are Whittemore at 978-681-8833 and Schundler at 732-287-2244. These two companies are the major suppliers of vermiculite in the US. There is another product that can be used, one of which is Perlite, a volcanic glass that has similar properties to vermiculite and can be installed instead of vermiculite. If you are having trouble finding vermiculite in your area, call a few large garden centers in your area, to see if they stock Perlite.
When is the Pool Floor Installed?The time to install the pool floor is after the walls have been secured with the concrete collar, poured around the base of the walls. After that, you put on your pool coping and wall foam and face plate gaskets for skimmer and light and then install the pool liner.
How Much Vermiculite Is Needed for Pool Floors?It depends on the size of your pool; I have created this small chart to help you order the right amount of material to cover the floor areas with a layer that is 1-2" thick. Vermiculite is sold in a common size of 4 cubic feet, and you may be surprised at how light it is . Portland cement comes in 94 lb bags, and you may be surprised at how heavy these are! If storing your product outside, be sure to wrap it tightly with plastic or tarps, to keep any rain from touching the bags.
How is Pool Floor Vermiculite Mixed?Vermiculite is mixed on site and in a cement mixer called a paddle mixer, which can be rented at any rental shop. You will need Portland cement on hand to complete the mix. The ratio is 2 bags of Vermiculite to 1 bag of cement. The Vermiculite and cement go into the mixer and then you'll add about 2 ½ - 5 gallon buckets of water, until you reach an oatmeal consistency that you can trowel easily. Leave it in the mixer for about 20-30 seconds and that should do it. If it seems to loose and runny, add less water and if it's too stiff, add more water to the next mix. In the picture below, the fellow on the right is dumping from the mixer into the wheelbarrow, and then moving the mixture to the areas where it's needed. In the middle picture, they are bringing in buckets full of the mixture and in the left side picture, these guys are taking the easy route. They are using a combination cement mixer and pump, and are spraying the mixture down before troweling it smooth - faster and easier!
What about Pre-Mix Vermiculite?There is another product that I know as PreMix, which is a mixture of vermiculite and cement together in one bag. Just add water! This is the same product and will give you the same results, just without the need to mix two products together. Pre-mix product is sold under such names as Pool Base or Pool Mix. If you can buy it locally, it may be worth the extra expense, but if you have to pay large shipment fees, it can end up costing 30-40% more than buying both Portland and Vermiculite locally and mixing it yourself on-site.
How to Install your Pool FloorBefore troweling in the vermiculite you want to have your pool bottom approximately 2” below the finished level. This is done with string lines throughout the pool bottom to the finished grade or depth of the pool floor. To install your vermiculite pool bottom you will need:
- Cement Mixer
- Wheel barrows
- 4 to 6 five-gallon buckets
- Garden hose or water source
- Shovel, a steel bullnose trowel and a wood float