Jump to content

Hardie Plank Omitted 1/4" Gap


Recommended Posts

New construction house today had very nice install EXCEPT the1/4" gap had been ommitted. I find this issue very annoying.

Years back a Hardie rep signed off on an issue saying it would not affect the warrranty, will they do that now?

Anyone with an update on this issue? Installations before this requirement have not suffered by my observation.

Anyone seen any problems resulting from when it was not done?

How do Hardie reps handle this sort of thing now? The builder's superintendent was intractable -which was even more annoying as the clients are timid.



Link to comment
Share on other sites


I assume you're referring to the requirement for a gap above the head flashings. I suspect the 1/4-inch requirement is simply to ensure that whoever paints the stuff is able to get a good coat of paint on that edge above the flashings. When you think about it, slathering a lot of paint into a 1/4-inch gap could end up sealing the flashings to the edge of the siding instead of allowing drainage. I think it's just important to ensure that there is an uncaulked gap of some sort above them and that the edge is painted. I don't know that having a 1/4-inch gap is going to be any more beneficial than a 1/8-inch gap.

With Hardi products, the biggest ommission I see is the lack of any mounting/trim blocks, flashings or gap of any sort behind/over exterior lights, receptacles, crawlspace vents, exhaust fan outlets, furnace/water heater exhaust vents, combustion air inlets, etc.. It's not uncommon to find that the siding and trim has been perfectly installed and flashed around windows and doors and then find these other items done completely wrong.

The week before last I had a house up in Issaquah that was the first house I'd seen in 16 years where the Hardiplank detailing was textbook. It actually looked like whoever the siding sub was had been standing there with the installation instructions in one hand and the best practices manual in the other because it was beautifully done - which I've never been able to say before. Hope the folks at James Hardie find that sub and send him around the country giving classes on how to put the stuff on correctly.



Link to comment
Share on other sites

Thanks Mike, I appreciate your response. I called Hardie Technical today (as I was going to anyway) and recommended by Steve, and the response was polite an thorough. He said Hardie was looking for room for the flashing to be sloped for drainage of the flashing and that errors in any aspect would/could only affect warranty in that aspect, not house wide, as I expected.


Lake Oswego, Oregon

Inspector class of 1984

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...