James Hardie installation manual graphic illustration of proper gap for siding over shingles:
When it comes to the installation of HardiPlank siding, we are the only company we know of that installs this product correctly, in accordance with the Hardie Company’s own guidelines.
Trained by the James Hardie Company, we follow the James Hardie Installation Manual, which clearly states how their product should be installed. The page below is reproduced without alteration from the company’s most recent Manual.
As you can see for yourself, illustration 3.11 in the center of the page clearly states that “a clearance of 2 in. must be maintained between James Hardie siding and trim products and roofs…”
Despite this explicit direction, 99% of all the HardiePlank we see has been incorrectly installed – that is, the bottom edge of this siding is simply too close to the shingles under it. The gap is virtually always less than the company’s recommendation of 2 inches of clearance.
In addition, 99% of the time, whoever installed the Hardie siding did not paint the bottom edge of it, yet virtually every illustration in this James Hardie Manual says clearly “seal cut edges of siding,” with arrows pointing to where the new siding has been cut at an angle which matches that of the roof pitch (drawing 3.11).
Again, we are the only company we know that paints the bottom, cut edge of this siding so that it has the waterproofing that it needs. If anyone doubts that HardiePlank needs the waterproofing which paint provides, just read the statement at the very bottom of the page: “James Hardie siding and trim products must not be installed such that they remain in contact with standing water.”
This tells you that HardiePlank is not inherently waterproof, and elsewhere in the Manual the company makes that clear, by the way. This is not a criticism of HardiePlank. Indeed, it is tough stuff. My point is simply that it has to be installed correctly in order for it to last as long as it can, but most contractors just are not installing it the right way. They are not following the manufacturer’s directions.
So, if you want HardiePlank installed right, call NC Gutter Guys.
