I would like to put a sealer on our gypcrete floor before we move in because we don't have enough money to cover the whole floor.


I would like to put a sealer on our gypcrete floor before we move in because we don't have enough money to cover the whole floor.

Asked by James Sharp

The heating is in the floor. Later we would like to install tile in some areas and click together wood like flooring in others. We live in Interior Alaska there for have the additional difficulties of have fewer places to shop for products in stores and when shipping the cost and freezing conditions come into concern. Thanks Jim

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Joel Hirshberg's picture

Gyp-Crete, an underlayment manufactured by Maxxon was not designed to be used asflooring by itself as it is too soft and porous.

  • It's a light weight concrete used primarilyas an underlayment for sound control and fire resistance in multi-family buildings.
  • But it isalso used in residential areas to smooth out rough subfloors or to provide a substrate forradiant heated floors.

Soft and dusty

Although it's very stable chemically speaking, Gyp-Crete is relatively soft and becomesdusty which makes it challenging for flooring contractors.

  • There are lots of posts on theinternet about problems related to trying to glue wood, concrete or tile directly to Gyp-Crete.
  • This is because nothing sticks very well to it unless you use the proper primers andadhesives.

These specialty primers and adhesives are expensive, hard to find and usually toxic.Look up Maxxon, Hacker or Dependable as they all make a variety of products forprofessional use only. These primers and adhesives are not DIY type products. Theyrequire experienced professionals to install and I don't recommend that you do it byyourself.

Controlling the dust

When used under floating floors, Gyp-Crete does not need to be sealed or primed asthere is no off-gassing of VOCs, and no adhesive is required.

However, you should stillexercise caution if you plan on walking on the Gyp-Crete before you put flooring over it.If you can't afford to buy flooring at this time, you could lay down some 6ml plastic tocontrol the dust and then some plywood or RamBoard (a recycled protective covering) ontop to hold you over.

Silicates and titanium dioxides

FYI--Gyp-Crete is made with gypsum which is mainly calcium sulfate, Portland cement,silicates and small amounts of titanium dioxide.

  • The silicates and titanium dioxides arepossible lung carcinogens.
  • The dust from calcium sulfate and silicates has an irritantaction on mucous membranes of the respiratory tract and eyes.

There have been reportsof conjunctivitis, chronic rhinitis, laryngitis, pharyngitis, impaired sense of smell andtaste, bleeding from the nose and reactions of tracheal and bronchial membranes inexposed workers. Most of these symptoms arise from over-exposure to the dust on adaily basis which you might encounter if walking on it every day.

Some of Maxxon's Gyp-Crete products are Green-Guard Children and Schools certified,which means they're compliant with very low VOC levels; however, this does not meanthey are safe for people with chemical sensitivities or pregnant women; and low VOCdoes not always equate with non-toxicity or health.

To avoid exposing yourself to unknown chemicals requires knowledge and experience.You have to do your homework.

Let me know if I can be of further assistance.


Joel Hirshberg

For more information:

For more info on VOCs and healthrefer tothis poston my website.