From old farmhouses to houses built last year, we look under the floor, show you what is there, and fix the cause before anything else.
Lynden is farm country with a town in the middle of it. An older farmhouse and a newer home on the same valley ground can have very different things going on underneath.
An old farmhouse that has been added onto may have more than one crawl space under the same roof, each with its own access, its own ground cover or lack of one, and insulation from whichever decade it went in. Some of it may still be up against the boards; some may be hanging or lying on the soil. A home inspector in Washington has to report missing insulation between heated and unheated spaces, along with missing or inadequate vapor barriers over dirt floors, so these can turn up as notes when a farmhouse changes hands.
A newer house next door has a different list: a ground cover torn during a repair, or a downspout that dumps beside the foundation. Carrying roof water well away from the foundation and keeping the soil sloped away from the house matter on any lot, and on flat ground that slope has to be built in.
Gaps in a foundation can let mice in, and Washington's Department of Health advises sealing gaps larger than 1/4 inch to keep rodents out. That is a problem we help with after the pest control company has done its part.
Crawl space insulation for floors with missing, sagging or fallen insulation, done to suit a vented or sealed crawl space.
Crawl space cleaning to remove old insulation, debris and soiled material before anything new goes in.
Crawl space vapor barriers for farmhouse crawl spaces with patchy or no ground cover.
Crawl space encapsulation when a sealed crawl space suits the house, after the water is under control.
French drains and foundation drainage and sump pump installation for flat lots where water collects against the foundation.
Basement waterproofing and crawl space dehumidifiers where a home needs them.
New insulation over a wet crawl space is money spent twice. DOE's guidance says moisture problems in the crawl space or around the foundation must be taken care of before insulating. We sort the water first, then the floor.
Droppings are handled with care. In Washington, deer mice carry hantavirus, and people usually catch it by breathing dust stirred up while cleaning droppings or nests. The state Department of Health says not to vacuum or sweep droppings, and to soak them with a bleach solution before wiping them up. Live rodents are a job for a pest control company first; after that, we can clean out soiled material and seal the gaps.
Some crawl space projects need a permit, especially when they add a sump pump, new wiring, drain lines or an exhaust fan, or close up the foundation vents, so we check with the City of Lynden or Whatcom County before work starts and pull any permits the job requires. We route sump and drain water away from the house to an approved outlet, and we check the local rules before any connection is made.
Sometimes, not always. A small Washington State University study of new homes in the state's marine and cold climates concluded that "with proper site water management, both conditioned and vented crawlspaces can be built successfully" in the Northwest. EPA's Indoor airPLUS program exempts marine climates from its sealed crawl space recommendation. The study also found sealing changed radon levels: in its marine-climate test homes near Vancouver, WA, a higher-radon area than Whatcom County, radon measured higher in the sealed crawl spaces than in the vented ones. A sealed crawl space is not radon mitigation, and Washington's code treats radon separately. Our guide on whether encapsulation is worth it goes further.
It depends on where the insulation goes. Under Washington's energy code, Whatcom County homes fall under the "Climate Zone 5 and Marine 4" column. In a vented crawl space, Washington's energy code calls for R-30 insulation under the floor, held tight against the subfloor. When a crawl space is sealed and brought inside the home's insulated envelope, the code lets the insulation move to the foundation walls, and the WSU Energy Program recommends insulating those walls to the same level as a basement wall, such as R-10 rigid insulation on the outside or R-15 continuous insulation on the inside. The code does not list a separate crawl space wall value, so we confirm the insulation plan with the building department when a project calls for it.
Yes, but in DOE's approach it moves from the floor to the walls. When a crawl space is brought inside the home's thermal envelope, DOE guidance is to insulate and air seal the perimeter walls and install a continuous sealed ground cover. In their cold-climate test homes, Washington State University researchers found fiberglass batts on perimeter walls with a vapor retarder on the inside face stayed near 100 percent humidity, and recommended foam instead. That is a research recommendation, not a code rule. See crawl space insulation.
Mice look for shelter and a way in, and a crawl space with gaps in the foundation or torn vent screens can offer both. Washington's Department of Health advises sealing gaps larger than 1/4 inch to keep rodents out. If they are already living there, call a pest control company first, then have the soiled material cleaned out and the gaps closed.
We also work under homes in Bellingham, Ferndale and Blaine, and in Everson, Sumas, Custer, Birch Bay, Sudden Valley and Deming.
Tell us about the house, or send photos or the crawl space section of your inspection report. We will go under the floor and show you what we find.
We will be in touch to book a time to look under the house. If it cannot wait, call (360) 555-0163.
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