Chapter 3 of 17
Skirting and ventilation
What skirting is actually for, and why blocking its vents causes the damage it was meant to prevent.
1 min read
Skirting encloses the space between the floor and the ground. It keeps animals out, protects plumbing from freezing, reduces heat loss, and tidies the appearance. Most communities and many jurisdictions require it.
Critically, it must be vented. The ground under a home gives off moisture continuously, and that moisture has to escape. Unvented or blocked skirting turns the crawl space into a humid box directly beneath your floor, and that is a leading cause of rotted floor decking, failed insulation, mould, and buckled flooring.
The most common owner mistake is closing the vents for winter to keep pipes warm. It is well-intentioned and it causes damage, trapped moisture condenses on cold surfaces and stays. Insulate the pipes instead and leave the ventilation working. If your climate genuinely requires a different approach, a fully sealed and conditioned crawl space is an engineered solution, not something to improvise by blocking vents.
Walk the skirting twice a year. Look for cracked or missing panels, gaps at corners, panels pushed out from behind, which often means an animal, and vents blocked by soil, mulch, leaves, or stored items.
Keep the ground sloping away from the home on all sides, and keep stored items out of the crawl space. Boxes and timber under the home hold moisture and give rodents somewhere to live.
Key points
- Skirting must be vented; blocked vents cause the damage skirting prevents.
- Do not close vents for winter, insulate the pipes instead.
- Inspect for cracked panels, gaps, and blocked vents twice yearly.
- Slope the ground away, and store nothing under the home.
Watch out
A musty smell indoors, condensation on windows, or springy floors usually mean a crawl-space moisture problem, not a plumbing leak. Look under the home before you open a wall.