"We use this on our timber outbuildings once a year. One coat sprayed to saturate the wood. Full water repellency doesn't last a whole year but WaterSeal does maintain the condition of the timber, allowing it to turn a natural grey colour over time, which fits into the countryside far more sympathetically than the usual black/brown/green/orange timber preservatives."
"Being water based this has low odour and is easy to clean up. However on some surfaces it can be harder to apply compared to the old solvent based formulation.
With porous materials like concrete, brick and mortar is it quite easy to apply this water sealer as it just soaks in. However when trying to apply it to vertical wooden surfaces you'll find it will run off before soaking in resulting in huge wastage. This is because wood has some natural oils and is less porous.
On wood the trick is not to use a brush but to spray on a light layer with a relatively fine spray. The droplets will cling onto the wood long enough for it to soak in. Once the first coat has soaked in the second coat is easier to apply.
Another thing to note with the water based formulation is that you will not be able apply more coats once it has dried as it will repel itself."
"I've used this stuff for the first time in the last week. It certainly makes the masonry water-repellant - there's been heavy rain since, and the water visibly ran off the brickwork and mortar, which was pretty porous before. How long it stays effective remains to be seen. I previously (10 years ago) used a solvent-based waterproofer, which over time became ineffective. The fact that this one is water-based means that it's much more user-friendly to apply."
"I bought this product on the basis that it was the original solvent based material that I had previously been pleased with, and the current catalogue clearly shows N and Xn hazards indicating a solvent-based product. But it's not!! It's a thin water based product which is not easily absorbed and just runs off unless the surface is extremely porous and dry.
I took the can back and explained the incorrect description and left with a tin of the No Nonsense equivalent, which is solvent based and others have found to be good.
The Thompsons product may be OK under ideal conditions but I was waterproofing a chimney and need the best result I can get."