Base Insulation Layer Material Quantity Overstated?

Am I the only one who had twice as much perlite and portland than necessary for the base layer? I ordered a 4cuft bag of perlite and only used 15 gallons of it with 3 gallons of portland. The channel is full, so did I do something wrong or did y’all also have more than needed?

Welcome to the BrickWood forum, and thanks for the question.

This is (sort of) a supply chain issue. Perlite comes in either very small or very large bags. It appears there is no in-between (and if there is, I’d love to hear about it!).

The small bags are intended for gardeners potting a few plants and mixing the Perlite with garden soil. The large bags are bulk versions for nurseries.

It takes something like 10 of the small, expensive bags to make the base layer mix. That adds up in cost very quickly.

One large bag will more than cover your need, and though I haven’t checked the price lately, it cost less than two of the small bags (under $20).

The bonus was that my spouse and I were able to mix the remaining Perlite with topsoil and fertilizer using the concrete drum mixer I purchased for the oven build. Nothing is wasted!

In short, you did nothing wrong, and you saved a lot of money by purchasing your Perlite in the larger bag. It rubs me the wrong way a bit in terms of environmental concerns, but I balance that against less packaging, less handling, and more efficient transport.

Thank you so much for confirming! That’s such a relief!

BikerBudMatt, it does look like perlite is available in 2cuft bags. Don’t know that there are many vendors, but I was able to locate this one. $18.95 for 2 cuft. Our 4 cuft cost $51.88, so might save funds and excess product for others.

GROW!T #2 Perlite, Super Coarse, 2 cu ft – East Coast Hydro

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