• 0
Kate Royce

Sealer

Question

I'm working on a high school building in New England with ground face CMU. Is a sealer, either factory or field applied, really necessary? And if so, which method is best?

Share this post


Link to post
Share on other sites

3 answers to this question

  • 0
4 hours ago, Kate Royce said:

I'm working on a high school building in New England with ground face CMU. Is a sealer, either factory or field applied, really necessary? And if so, which method is best?

Ground face masonry unit manufacturers have written positions about this, so it would be good to contact them directly. Generally speaking, a sealer is applied at the factory on ground face units so they achieve a higher luster. In addition, a sealed unit makes mortar smears easier to clean.  Some sample kits of ground face I am aware of have a "second sealer coat" applied, so the decision maker has an idea of what ground face units will look like after a post-construction sealer is applied. Post applied sealers will seal the ground face unit as well as the mortar joints.  

Share this post


Link to post
Share on other sites
  • 0

Edwin raises a couple excellent points Kate - the sealer could be applied at the plant or in the field depending on the final desired results. If the end goal is water penetration resistance, however, then a post-applied sealer is the way to go. The follow-up question I often receive is whether a sealer is needed for water penetration resistance if the units and mortar also contain an integral water repellent. Per NCMA TEK 19-2B, general industry guidance doesn't suggest that both integral water repellents and surface sealers be required in all applications, but does recommend considering when such redundancy may be warranted (as discussed in the TEK). If a post-applied sealer is to be used on units/mortar containing an integral water repellent, the compatibility of these two materials should be verified with the admix/sealer manufacturer.

TEK 19-02B.pdf

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now