Parged Finish on the Foundation

Parged Finish on the Foundation

One way we lowered the cost for our pre-fab cabin foundation is to use Thoroseal parging instead of a stucco finish on the block.

Thoroseal is not actually Thoroseal anymore. It is now called MasterSeal 582. There are a lot of variations of MasterSeal. The one that used to be called Thoroseal is MasterSeal 582. It is “A waterproof cement-based coating for exterior below-grade for concrete and masonry.”


Formerly known as Thoroseal, manufactured by Chemrex, has been rebranded Masterseal 581 (dry) or 583 (wet, in bucket), since Chemrex was purchased by BASF. Masterseal is a cement-based, waterproof coating for concrete and masonry. It is NSF approved for sealing concrete or masonry tanks storing potable water. It is also used to seal the concrete base of culvert tanks.

Sealers Approved for Contact with Potable Water

Concrete saw cut a new crawl space opening

First thing in the morning I saw a truck so I dressed warmly and went to see what was going on. There was an odd smell, kinda like burning something strange.

They had cut out a new crawl space on the other side of the foundation.

Crawl space cut open on the other side of the cabin

I had my doubts about the original location of the crawl space entrance.

They had moved the piece they cut out to the other side and mortared it into the original crawl space opening.

Parging with MasterSeal 582, a waterproof cement-based coating for exterior below-grade for concrete and masonry.

A parge coat is a thin coat of mortar, similar to stucco, but slapped on with a brush. Using a waterproof kind of mortar coating accomplishes both with one process. Less labor.

MasterSeal® 582
Formerly Thoroseal

They used MasterSeal 582.

MasterSeal® 582 Foundation Coating Waterproof Cement-Based Coating for Exterior Below-Grade concrete and Masonry

  • Formerly Thoroseal
  • Cementitious Waterproofing
  • MasterSeal 582 Foundation Coating
  • Waterproof, cement-based coating for exterior below-grade concrete and masonry.

MasterSeal 582 resists both positive and negative hydrostatic pressure while allowing interior moisture to escape without damaging the coating.

Mixing MasterSeal 582 with a slow-speed drill and mixing paddle

While one man mixed the material up with a drill and a mixer attachment, the other man thoroughly cleaned any mud on the top of the footer and any mud that had gotten on the wall and dampened the wall surface.

First coat parging with MasterSeal 582

They brushed the material on thoroughly. They covered from the footers to the top of the foundation wall. They really pushed it into the block.

Where the crawl space opening was

They walked around and checked everything when they finished, dabbing a few places again.

This wall where the opening to the crawl space used to be after the first coat of MasterSeal 582.

Where the crawl space opening is now

This is where the crawl space is now. They filled in the block openings with mortar.

Second coat of Thoroseal

The next day they came back and put on another coat.

Taylor Fowler with Fowler Excavating has really worked with us to keep within our budget. If you are building anywhere near Hendersonville North Carolina, you could not do better.

The cabin is from Westwood Cabins. You can see more photos and floor plans at and

Next, the sill plate.