Fixing hardie plank siding?

[SC Maintenance]

My house needs painting and on inspection I found some strange circular cracking on my hardie plank. Its only in this one area, on the second floor between 2 windows. The cracks look odd to me?

Has anyone seen this? Has anyone repaired this? Hardie says it can be repaired with cementitious patching compound. I can't find the Hardie brand. I found something close from DAP?

Any expertise on this at all would be greatly appreciated. Pics of the actual cracks below.

 

[Kansas_Ron]

I am sorry to see the Hardie siding do this. I have the same material on my home. Perhaps the planks between the windows have been installed too tightly against the window frames. Expansion due to heat is happening and the force is creating the cracks. This is just speculation on my part.

 

[doitmyself]

Since most of your cracks seem to start at the bottom of the plank and IF they are wider at the bottom and then get thinner, that would indicate some settling occurred in that section of the house framing. Other reasons might be inappropriate installation, i.e., nailing.

Repair? I'm torn between using a flexible caulk vs. the cementatious acrylic mortar. If there is any movement at all, a hard product will crack again.

 

[SC Maintenance]

using a flexible caulk

So your thinking just something like a DAP dynaflex - basically a synthetic caulk designed to stay flexible?

I need to get up there, but I don;t think the cracks are very big at all. It could have settled but there is no cracking of any interior drywall at that location or any other thing I can find.

 

[doitmyself]

So your thinking just something like a DAP dynaflex - basically a synthetic caulk designed to stay flexible?

I need to get up there, but I don;t think the cracks are very big at all. It could have settled but there is no cracking of any interior drywall at that location or any other thing I can find.

I'm no expert on Hardie board specifically, but I have quite a bit of experience with building repairs and principles. Your link states their cementitious compound is for minor surface repairs, implying to me that it is a filler for non-moving repairs (dents, holes, surface-only cracks). If your cracks are all the way through the board and IF movement continues to happen (expansion-contraction), then any hard, non flexible repair is just going to crack again (same as a interior plaster repair in an old house that moves seasonally). Some semi flexible product that would bond the two crack edges together seems appropriate. Liquid nail type products (Fuze It Max) are incredible, IF you can get them pushed deep into the crack. A flexible caulk "might" last awhile. I've had decent luck using a bridging technique of fiberglass cloth covered by flexible compound (takes a lot of skill to blend and hide).

Yea, I'm not sure what your solution is besides replacing those pieces. The DAP platinum markets itself as a fix-all solution, but you know what they say about "if it sounds too good to be true". Maybe seek other expert help - I'm not one of them . Sorry.

 

[PimTac]

What is behind that wall?

 

[AndyB]

Siding was installed to tight. No room to move.