One reason for the porous nature of the gap can be attributed to old asphalt saturated fiberboard that had fallen apart.
Expansion gaps smooth stucco siding.
James hardie recommends that a slip sheet joint flashing is installed behind each butt joint in the siding.
Quikrete has a stucco repair product that is textured to match the surrounding stucco and can fill gaps up to 1 2 an inch wide.
Both certainteed and jameshardie as of september 2008 have made clear that siding butt joint gaps should never be made that is.
Wet your finger and gently wipe the caulk in the gap to give it a smooth rounded appearance.
Clean out the crack using a scraping tool and a wire brush so that there is no loose material and the caulk has a good surface to bond to.
There is no need to leave a gap for expansion.
After that the pro will apply a new stucco base coat.
But i just read an fhb article working with fiber cement siding from june july 2001 that states that on walls 12 or longer hardie recommends you leave 1 8 gaps between the lap pieces and the trim and between the butt ends of adjoining lap pieces to allow for expansion.
Wipe away any excess caulk.
Siding butt joint treatment.
The pro s first step will be to power wash the home.
Asphalt saturated fiberboard designed for expansion joints.
This means that the boards should be touching each other when they are installed.
Do not deliberately leave butt joint gaps in fiber cement lap siding and that they do not recommend caulking field cut butt joints in their board type fiber cement siding products.
Use sanded caulk any time you use sanded grout and in joints 1 8 inch or wider.
A stucco pro will simply apply a new texture over the existing one.
Is there a smart trim type 1 x 8 or 1x10 material with a rabbeted top and bottom to allow a flat installation and provide the proper drainage at the horizontal joints.
Unsanded caulk has a smooth appearance and texture.
Fill any low spots or remaining gaps with additional caulking until the gap.
Hardie boards should be joined in moderate contact.
This affected most of the fiberboard between the patio and house.
The clients and their architect are also looking into possibility using sheets of fiber cement 4x8 to provide the low maintenance and smooth look but.
Sanded caulk has particles in it that help it adhere to wet surfaces and expand in larger gaps without cracking.
It has a grainy texture and appearance.
Stucco is not an option.
It recommends filling the gaps with caulk.