"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."
"Had an unopened tin of Thomsons water Sealant in garage for about six years and decided to use it on my roof after power cleaning same. Went on nae bother and could see it leaching into the porous tiles. Bought additional tins to finish the job only to find that the Thomsons formula had changed from solvent based to a water based product. This water based product was milky in appearance and did not absorb into the tiles easily. I took my tins back and bought the cheaper No Nonsense range solvent based product which went on a treat. Maybe I'm old fashioned but to me a solvent base is better protection from water/rain than a water based product. I can only think that Thomsons altered their formula because a water based product is "environmentally friendly" and is easier stored and does not carry the same restrictions as a solvent base plus they "talk up" the new product benefits. Its solvent based for me every time !!!"
"I had previously used the spirit based Thompson's Water Seal. It advised 2 - 3 coats. Having done this the bricks were completely waterproof. You could throw a cup of water at it and the water ran off in tiny beads - NOTHING absorbed. Have just used the ONE COAT version (water based) and have thrown a cup of water at it - the water did NOT run off - it was absorbed. Will need to do more coats."