How to Weatherproof a Wood Porch Floor
LESLIE: Now we’re going to talk to Alec in Minnesota who listens to The Money Pit on KNUJ about weatherproofing an outdoor porch.
Alec, how can we help?
ALEC: I built an outdoor porch and we have a wood floor which we have to paint every year and still find that it is deteriorating. And I have heard that there is a coating, probably a plastic or a rubber-type base, that you can apply to it. And I’m wondering if that is the case.
LESLIE: Hmm, well I’m not familiar with that but I can imagine why you’re having this problem. It’s because you go through such major freeze and winter and cold weather and then the summer you have extreme heat, so you’re getting such an interesting mix of temperatures that of course any sort of paint that you put on is going to sort of just deteriorate over the seasons and need to be touched up every summer or winter.
TOM: Alec, is this a concrete porch or a wood porch?
ALEC: No, it’s a fir floor.
TOM: Fir floor.
ALEC: It’s …
TOM: Does it drain well? Does the water run off it well?
ALEC: Drains well but, of course, whenever it rains or it snows it gets moisture on it. And I just would wish there were some kind of a coating that could seal it.
TOM: Let me ask you this. Have you ever completely stripped that floor? Has it ever been sanded down?
ALEC: We do that. We did it this fall. We got a very nice paint job on it and probably – we tried to buy the best paint we could.
TOM: Did you prime it? Did you use a primer?
ALEC: Oh, yes. Yes.
ALEC: Well, this is a self – we not only primed it but this is also a self-priming paint, so it should be twice as good.
TOM: Well, I don’t know about that. I’ve never heard of a self-priming paint.
ALEC: Well, that’s what it said. It did not need priming. But we primed it anyway, just to be sure.
TOM: You know, the qualities that make a good primer are quite different than the qualities that make a good topcoat. That’s why there are two materials out there. It’s not designed to make you do more work but the primer itself has adhesive qualities that the paint does not have. And so if you strip the floor down and you put this what you’re calling a self-priming paint on, I do wonder whether or not you got the adhesion that you needed to get.
If I was doing a wood floor, I would strip it down, I would paint it with an oil-based primer like a KILZ or something like that, and then I would use an oil-based floor paint. I would not use a water-based floor paint. I would use an oil-based floor paint because a wood floor is one of the very few applications where you want to use an oil-based product because it’s just a lot more durable and it has better abrasion-resistance than any of the latex products.
The only other thought I have for you is that, again, if you stripped it down, you may be able to use an epoxy painting system like an EPOXYShield product or something like that where you mix up a two-part epoxy. And that stuff binds like crazy to all sorts of material.
LESLIE: Yeah, but would that be a freezing hazard in the winter?
TOM: Well, I don’t think so. You know what I mean? You could use an additive, an anti-slip additive like a sand or something of that nature, that would make it …
LESLIE: To give it a grip.
TOM: Yeah, exactly; give it a grip. So there are a couple of options for you. But you concern me when you say that you used a self-priming paint. I’ve just never heard of that and I know that there’s no excuse – there’s no substitute, I should say, for not using a really good primer because that really is what makes the paint stick.
ALEC: Well, we had just refinished a flat roof over the two-car garage and with a rubber coating, you know a rubber …
TOM: Right, a rubber roof.
ALEC: And I’m just wondering if something like that would work. But I’ll have to experiment.
TOM: Well, the only other – let me give you one more idea – radical but it would absolutely work and it’ll never come off – and that is a fiberglass deck. You know, in many cases where you have balconies these days on homes – say you have a second-floor, master bedroom balcony – those outside wood decks are coated with fiberglass. The fiberglass is basically installed. It’s a specialty roofing contractor that does it. They put down the fiberglass and the mesh and it’s built up and it has traction in it; it has a rough surface to it and it never, ever, ever leaks. It’s like standing in a fiberglass bathtub. But it doesn’t look nearly as nice as your wood floor. So if you want to completely seal it, that’s another option. But I really think that if it’s painted with the right kind of primer and paint, it shouldn’t come back.
One other thing you might want to look at is, underneath this floor, make sure you don’t have a lot of moisture building up in the crawlspace underneath this floor. Because if you have a lot of humidity, that can also force the paint to lift off.
ALEC: That fiberglass buildup or coating, that is available and would be an impervious surface?
TOM: Completely impervious surface and it has to be professionally installed. Yeah, you have to find a fiberglass deck contractor that knows how to put that in. I’m sure if you check with the roofing contractors in your area, they’ll either do it or they’ll know somebody that does it. It’s a pretty specialized service but it happens quite frequently in new construction.
ALEC: Is there a certain brand?
TOM: No, it’s done by hand. It’s something that’s done by hand. They actually build the fiberglass right there on your porch to fit.
ALEC: OK, that’s what I’ve heard of. You know? OK, I was just wondering if there was such a product and I will investigate it. Thank you.
TOM: OK, Alec. Thanks so much for calling us at 888-MONEY-PIT.