What would you use to caulk cement siding? I’m not crazy about relying on caulk to keep the water out, so I’m thinking of using 3M 5200 a marine polyurethane with incredible adhesion. So much so that they don’t recommend using it on anything that needs to come back apart. I used it once to install a fitting in the boat that i later had to remove. I ended up having to grind it out to remove it, so their warning is deserved. Anybody see a downside to using it on Cement Siding?
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Besides overkill and wicked expensive? Make sure what you buy is fresh, and it doesn't like the cold at all.
ChuckT: Dap makes a new caulking and I believe it's called Sidewinder and can be used on cement siding and in below freezing temperatures. Best Regards. Dale
We have had good results with 2 sealants. First one is applied under the siding before you install the piece. We use a poly saealant for this step. Our brand of choice is NPC solar seal #900. Comes in a wide range of colors. The sealant we use for the joints and seams is DAP acrylic latex caulking. We have never had a problem with it to date.
A grinder? this doesn't mean that it gets hard or brittle does it? if that's the case I wouldn't use it. I like using one part urethane caulk for Hardie siding Mostly because of the same reasons you mentioned. My brand of choice is NP-1 ( around $5.00 per tube in my neighborhood). Takes paint, sticks anything to anything in most climates, and will still be soft and flexible when your kids are grown up. ( you do have teenage kids don't you? hee hee) Sux to work with, but makes for peace of mind.
The 5200 doesn't get hard, but it sticks so well, I had to grind away the actual fitting to re-open the hole it occupied. It wouldn't come out.
I guess it just becomes a matter of cost then. If you consider the overall cost of the house, a couple of hundred for a premium grade caulk may be worth that peace of mind.
By the way... I have always used a tin shingle behind the joints. I've never had much faith in tar paper, I think it disintegrates too soon considering you are using a siding that is s'posed to last for 50 years.
Our Hardie rep. recommends a piece of tar paper behind the joints 6" wide and overlapping the piece below. The problem with caulking the joint, is that the caulk weeps out and is difficult to remove completely leaving an unsightly joint. (we use double layer grade D paper.
steve
I used OSI Quad sealant.
It went on well, smoothed nicely, was "on the approved list" from the fiber cement siding mfg, the color was a darn close match, and it was paintable after a suitable drying time.