Hardie siding: failed caulk on butt joints, flash and re-caulk?
whitehawk7
| Posted in General Discussion on
Siding was done by prior owner on this house (post-requirement to flash instead of caulking butt joints, but here we are). I’ve started removing the failed caulk from the butt joints with the intention of re-caulking with some masterseal NP100 which I think will handle the flexing much better than whatever garbage is in there currently. Should I look at sliding in & nailing some form of flashing under the butt joints before caulking? (joints vary in width from 1/8″ to nearly 1/4″…
edit: forgot to mention that most of the time pulling out the old caulk is removing the paper it has adhered to behind it as well
Replies
I’m pretty sure you’re not supposed to caulk the butt joint. I’d go to the Hardy site and find out.
You are correct - it was not supposed to be caulked in the first place. My question is: in light of the improper installation that was done, and without funding to reside the home, what is my best option for addressing the failed caulk joints now?
My thought was to remove the failed caulk (razor to cut along edges of joint and then pull out) and either re-caulk with a superior product (poly hybrid) or flash under and then re-caulk. I believe the large gap in the butt-joints would be rather unsightly to leave uncaulked.
They make some sort of piece to go between them butt joints I’ve seen them. I don’t know what they’re called.
If you recall it, no matter what you use you just gonna have a problem again
Flashing. Strips of metal (I guess you could use any sort of membrane) flashing being each butt joint.
Unsightly or not, it's against manufacturer recommendations for the installation of the product. When I sided my shed with Hardie, I wasn't too strict on exact tolerances, but I did make sure there were gaps for expansion/contraction.
If I were in your shoes, I would:
1. Cut out all the caulking
2. Take down all the siding that needs to come down to get to the re-work joints (being careful not to damage any of the planks)
3. Install the flashing behind the butt joints
4. Make sure each butt joint was primed/painted/sealed on the edges as well as a few inches on the backside of the joint
5. Put it allllll back up, carefully
It's a simple task, but it will take you a weekend to get through it because of the sheer amount of siding to get through.
If you see the attached image, I added corner flashing on all the corners of my shed. This was...overkill. It was like 16" wide but I just had it laying around. Basically, I had some left over after these corners and cut up strips to use behind each butt joint. This is imperative that you have these flashings behind the butt joints, at least the manufacturer calls them out for a proper installation.
In the slate roofing world there is something called a bib flashing. It's a 5" wide piece of metal that you crease down the middle at a small angle like 15 degrees. I've used them on hardi siding just like you would on slate. You simply slide it under the siding and the crease in the metal gives it a friction fit. No nailing required. Just push it up slightly past the bottom edge of the hardi board and walk away. I think this is way better than trying to nail in the slot between two boards. You would be surprised how well it tucks in, and I've yet to have one fall out.