Caulking Hardiplank Lap Siding

The nails holding up the siding should not be caulked.

Caulking hardiplank lap siding.

It will look okay on day one but caulk is not designed to be used as a touch up and it will weather at a different pace than the siding. This technical bulletin is an explanation supporting the announcement made by james hardie on september 8th 2008 withdrawing its recommendation on the use of caulk at field butt joints for hardieplank lap siding. Apparently no one here read the technical bulletin 9 that james hardie released in 2008. Flashing acts as a waterproofing layer for this type of siding and caulking will prevent the flashing from doing its job.

Joint flashing is recommended for all hardie lap siding now. Deterioration of the caulking in the joint has become a maintenance issue for home owners over time. A diyer or a novice painter might attempt to achieve a cleaner look by caulking the siding nails but the nail is guaranteed to push the caulking material out within a few months. When james hardie siding products butt into wood based materials a 1 8 gap will allow for expansion and contraction of the wood based product.

Many professionals like those at james hardie also agree that you should not use caulk on fiber cement siding unless there is no metal flashing underneath. 152 4 mm wide 1 in. James hardie also does not recommend applying caulk to the horizontal overlap between siding planks see figure 2. Osi quad product brochure.

Caulking around windows doors eaves and trim edges gives added insurance that leaks will not occur. Similar to paint previous coats of. Is the old caulking removed before new coats are applied. 12 hardiplank james hardie warranty claims information tel.

Hardie no longer recommends the caulking of any joint in their lap siding colorplus or primed. James hardie color match caulk osi quad caulk for exterior door window and siding applications color matched to james hardie colors uv water resistant will not crack or yellow 1 tube covers 29 lineal feet at 1 4 bead width or 13 lineal feet at a 3 8 bead width paintable. 25 4 mm on overlap no caulk figure 1.