Meter readings of 5.1% to 6.9% shaped how this Bothell garage was coated. A sealed slab, then Smoke flake polyurea, finished in January 2026.
Bothell concrete in January is rarely bone dry. This homeowner had a two-car garage with charcoal walls, an overhead storage rack and a water heater in the back corner. The bare slab was stained and dusty, and it was full of shelving, bikes and bins. The plan was a garage floor coating in Bothell that would look sharp against those dark walls and stand up to wet winters.
What made this job interesting was the moisture. The meter readings told the crew to slow down and do it right, and that is what happened. The finished floor is Certified Penntek polyurea in Smoke flake, completed in January 2026.
At the free consultation on January 8, the meter read 5.1% and 5.2% in two spots. That is a normal starting point for a Northwest slab in midwinter, and it is why Cascade tests every floor before quoting.
When the crew came back to prep, they tested again. After grinding, a reading on the slab hit a maximum of 6.9%, with the garage air at about 80% relative humidity. Moisture moves up through concrete, and if it is trapped under a coating it pushes back. That is the most common reason coatings bubble and peel in this region.
So the work was spread over a few days instead of one. On January 15 a clear first coat went down over the ground slab before any color. Cascade uses a two-layer moisture barrier system when a slab needs it, so the polyurea above it has a sound, sealed surface to bond to. Our post on moisture in concrete and garage coatings explains the science in plain terms.
The floor was finished on January 17. The control joints were kept as straight lines, the entry step got the same flake, and the stem walls along both sides were coated to match.
Smoke Evolution is a mid-to-dark grey blend with black, grey and white chips. Against the charcoal paint it looks deliberate, like the whole garage was designed together. Up close the white chips keep it from feeling heavy.
Darker flake has a practical side too. Tire marks, road grime and the drips that come in on a wet car blend into the pattern. Next to a water heater, where the odd leak can happen, a sealed floor also means water stays on top where you can see it and mop it.
The polyurea bonds chemically with the concrete using a silane adhesion promoter, at over 1,300 PSI. Before the coating comes up, the concrete will come up. That only holds if the slab underneath is dealt with properly, which is why the moisture work above matters as much as the coating.
The polyaspartic topcoat is non-porous. Oil, gas, grease and winter road salt sit on top and wipe up. See it for yourself in the Penntek Stain Test, and find more durability tests on our demo page.
The floor carries a limited lifetime warranty backed by Penntek, the manufacturer, and Cascade registers it on every job.
Bothell sits at the north end of Lake Washington, and its winters are long and wet. Garages here often sit on slabs that take on moisture from below and from cars that come in dripping. Testing is not a box to tick. It decides what system goes on the floor.
Read more about our garage floor coatings in Bothell, or see a Bothell garage with coated steps and stem walls in Wild Dove for a lighter grey.
There is no single number that fits every slab. We read moisture at the consult and again before installing, then choose the system. When a slab needs it, a two-layer moisture barrier goes down before the polyurea basecoat.
The usual cause is moisture coming up through the slab under a coating that was put down without testing or proper prep. Grinding opens the concrete, and testing tells the crew whether a barrier is needed first.
No. The barrier sits under the basecoat. The flake and topcoat on top are the same, so the finished Smoke floor looks like any other.
Wondering what your slab reads? Book a free in-home quote and we'll test it on the spot, or call 425-226-6085. Nicole and Sheldon own Cascade and are licensed, bonded and insured.
Here's just a few of our previous projects.
