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Wood preservative for exterior trim

My house is about 13 years old and its due to be painted. I had to replace a good portion of the trim due to the builder not adequately sealing the bottom of the trim. Therefore it swelled and needed to be replaced. My question is that im looking for a good exterior wood preventative that is acrylic based. I would like to seal over it, and then paint it. I was looking at the Thompson's WaterSeal 1 Gal. Clear seal, but it doesn't say anything about the type of sealer (latex or acrylic). Would this be a good product for what im using it for? Or does anyone have any other suggestions.    


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Posted 2015-07-04T18:53:23+0000  by NBBuilder NBBuilder
If you had asked first, I would have suggested using one of the PVC trim materials like Azek instead of wood.  It eliminates all the problems associated with wood and makes a great substrate for paint.  But it's too late for that now.

You don't need to "seal" wood before painting.  A good quality primer and two coats paint is more than sufficient to protect the wood.  It's also a good idea to prime all the surfaces of exterior trim, including the back, before hanging it.

As for you old "wood" I have to wonder if it was actually wood?  Could it have been some kind of composite material?  Wood wouldn't normally swell that much when exposed to moisture and would contract when things dried out.
Posted 2015-07-05T03:31:14+0000  by Adam444

DON'T use Thompson's WaterSeal under paint! The same properties that make water bead on it, will make paint also not adhere to it !

I agree with Adam444 advice. Prime and paint before installing, payng special attention to the bottom edge and slightly onto the back side. Water does a "teapot" effect, running down and whipping underneath and backward. These are edges that are often difficult to paint once a bottom board is installed, due to its closeness to the ground.

I have used the Azek trim "lumber". It is more money up front, but you will never have to worry about rotting again. Although plastic, it is worked just like wooden boards with common tools and fasteners.
Posted 2015-07-06T05:39:02+0000  by ordjen
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