(51 of 58 customers found this review helpful)
Temporarily repels water
No Wood Preservative
Reapply 4 times a year
Thompson's water seal is a water repellent, and not even a good one. It will repel water on wood for about 90 days, so if this is your product of choice reapply it every 3 months to achieve that water beading illustration the Sales & Marketing people use on the T-V Ads which have made them so well known.<br /><br />Exterior wood is exposed to mildew, the air is laden with mold spores, you and I inhale them by the millions with every breath. A water repellent is only of minor value, what is required for wood is a wood preservative, something to resist decay, insects, and mildew. This product has none of those abilities. I have no idea what good it is, but they sure sell enough of it. <br /><br />In the 1960's and 70's you could purchase effective and very useful, Water Repellent Preservatives Some brands were Woodlife and Cuprinol. Woodlife contained 5% Pentachloraphenol, a very good wood preservative, and effective fungicide to prevent mold and mildew, but a very toxic chemical compound. In the 60's you could have purchased the Penta, as was its brand name in 5 gallon pails. Today it is illegal for anyone to sell it to you over the counter. The limits of what can now be sold have been restricted by the government, and the preservatives neede for wood in these products would seem to be regulated out of use. So you must decide if such products have value. Water repellency is not a big issue. Sealing wood from moisture change was never possible, but slowing the absorption of moisture, and the subsequent drying of wet lumber by coating the wood has some value. Stress from wet & dry cycles causes cupping, checking, warping and splitting. The slower those changes the lower the stress created, and the less pronounced the undesirable effects, so water reistance is of some value.
How long have you owned it:
No, I would not recommend this to a friend.