To thin or not to thin
Is thinning a sealer recommended? The obvious answer is “no.” Anytime you alter a sealer’s formulation you risk affecting its performance — not to mention voiding any stated warranty.
Is it done? Of course it is. Some contractors thin a sealer to facilitate better penetration of the first coat, and then apply following coats at full strength or apply additional coats to achieve the build-up needed.
In some situations — for example, when troubleshooting special circumstances — you may want to alter the product. But in these special situations, the alteration should be done on a case-by-case basis with the advice and recommendation of the product manufacturer.
There is an added concern regarding solvent-based products governed by VOC regulations. By thinning solvent-based products you might push the VOC above the legal limits, which would be illegal.
Manufacturers typically offer a variety of solid levels to avoid the need to dilute products.
