What are you going to seal it with?? Using block filler( which you should) would require at LEAST a 1 inch nap.

I have used a 3/4" nap in the past and it worked okay, but usually the bigger the better. The problem is that once you get that big fat nap loaded with paint, it can get pretty heavy to work with all day. Some block walls are not as porous and pitted as others so that is also a factor.

. The problem is that once you get that big fat nap loaded with paint, it can get pretty heavy to work with all day

I surely will not argue with that!The last one I did when still somewhat young( about 20 years ago) was an exterior concrete block building( small) and after a couple days,I was beat and I mean beat!As you say it depends on the block.

Christophern - I'm not sure what DH was planning on using. I'll have to find out. Is block filler different that the sealer to keep moisture out?

Paintguy - I'll have to look at the walls again.
"Some block walls are not as porous and pitted as others so that is also a factor."
Meaning if there's more holes I'll need more product and a thicker roller? Could you elaborate on that more?

I also should ask about the prep. I said the walls would probably needs scrubbed or at the least brushed up with one of those rough scrapper brushes but DH is saying whatever the stuff is he was going to use says you don't need to scrub them.

You can buy the sealer in 5 ga. buckets at Lowes if that helps narrow it down at all.

?

Thanks!

Sealer and block filler are two different things. The block filler is actually like a paint. Actually, using a paint is fine also....anything washable that forms a skin on top of the paint film will serve to keep moisture out. I prefer a waterproofing paint made by Grahams. The paint/block filler will do a better job at sealing moisture out than using a sealer.

As for the nap size, look at your walls and try to gauge the porousity or buy a 3/4" nap and a 1" nap and see if the 3/4" nap is enough. If the walls are very porous, then you will find yourself pushing hard on the sleeve to get the paint to fill in all the porous areas. Then you may want to step up to the 1". One thing for sure that you want to do with a painting project like this is keep your roller cover saturated with paint...do not dry roll or you will just tire yourself out fast.

Thanks Paintguy for explaining that better.

Well after talking quick with DH about this he was interested in using Drylok Extreme Latex Base Masonry Waterproofing. Any thoughts on that?

I'll also mention we have a 25 pt dehumidifier running pretty much all the time down there and have to empty it daily. Water doesn't get in. We built the house a year and a half ago. I was thinking for awhile maybe it was just moisture from the building material but I thought by now we wouldn't need to run it as much. I was digging around tonight reading some things and found that it needs to be really moisture free or it can cause problems with the paint drying etc and so forth. We have to push this project back for a bit now but that probably isn't a bad thing since we don't have a great game plan going on.

Here is a link that might be useful: Drylok

Coronado's Aqua Stop It is worth checking in to. You can talk the paint store into tinting it if you want. They will probably moan a little about doing it and they won't guarantee the color -- like not at all -- but if you want a buttercream yellow or tan or something, it's a lil something goin' on in the way of color at the same time you are treating the block.

While you're working on finishing the basement, the color in the ASI makes it look nice until you get the walls up -- or if you decide not to put walls up everywhere, you can just leave the ASI and it will look nicer than clear/no color sealer over block.

Here is a link that might be useful: Aqua Stop It