MasterSeal NP1 Gray Polyurethane Caulk

Time will tell, but so far I love this caulk. The original contractor caulk above a large window had deteriorated and I was getting water in the house with hard rains. I scraped that junk off and applied a nice bead of this on there. You can tell this stuff is good, it’s sticky like tar. I was able to get an even line with a silicone tool. It sealed up the joint really well. It’s been a few months in the hot summer sun so I went up and looked at it. It hasn’t shrunk at all. It’s still somewhat pliable which I think it a good sign.Ive used it in a few other places to touch up caulk that was pulling away. I also like that this is paintable. Hoping it lasts a few decades.

Fast delivery. Good product.

There are tons of caulk and adhesives to choose from no doubt; however this was recommended by a plumber who is a friend of mine. It is a bit more costly than the others, but well worth it as far as staying power. It is not as easily available, but I would recommend the wait. It does come it a few colors, so be sure and do your homework.

I just applied NP1 to a crack in a foundation wall to redo some work the foundation repair company had done, so I can’t quite speak to how well the product works over time. However, I’d like to make other people aware of a product labeling discrepancy I ran into. This was the second tube of NP1 I ordered from this listing (after getting the first and before starting my project I realized I needed more to get the crack filled completely). The first tube was marked “Grey” in printed black text at the base of the tube. The packaging on the second tube looked a little different, but had a barcode sticker attached to it describing it as “Grey”. I went ahead and started my project, using the first tube first. When that tube ran out and after I opened and started using the second tube I realized they were not the same color. Upon closer inspection, the second tube, while marked as grey was actually aluminum grey. The crack ended up having two different colors in it. The difference in colors won’t affect the quality of my project since I plan to paint over the caulk, however it’s important for others to keep in mind when they’re purchasing this product. Be sure to inspect the packaging prior to use. I’ve added a few photos showing the differences between the packaging as well as the difference in appearance between NP1 in grey (left) and in aluminum grey (right).

This product seems like it would do the job of closing a gap between my side walkway and foundation of house. It was very hard to press out so I ended up slicing the tube open. 1 of the 3 tubs did come out as expected but the other 2 were difficult to get out. It created a mess but eventually worked. Now I'll wait for wet weather to see if it keep the water out my basement

High quality caulking. Great for most projects.

As I have used this product on 5 projects in the last two months it gets easier and easier. Bonds and shapes to the cracks being filled well. Compared to other products this may a couple dollars more/tube but well worth the peace of mind.

Might be a good product, but I dont know. Maybe I got a bad batch? I bought about 12 tubes to go around the perimeter of my house. Went through 3 tubes..all 3 were so hard and dry the sealant would just barely come out. Way too dry to be effective on anything. Used 2 hands and squeezed so hard I'm surprised I didn't break the caulking gun.Waste of time and money.