Posts and pads
Posts stand on concrete pads or blocks and carry the girders. One can lean, settle into soft ground, split at the base or rot at the foot, and a broken pad changes the height of everything resting on it.
Crawlspace Post and Beam Repair in Kirkland
Typical cost in Kirkland
- Replace one post$350 – $850+
- Three to five posts$1,800 – $5,500+
- New beam and posts under one room$3,000 – $9,000+
The floor of a crawlspace house is held up by posts, pads, girders and sill plates, and repairing them is what this page covers. Kirkland Foundation Repair does that work in Kirkland when the floor bounces, sags or tilts.
Kenmore and Clyde Hill are covered too. Kirkland has 37 percent of its homes from 1960 to 1979.
What is under the floor
Girders and joists
The girder is the large beam running the length of the crawlspace, and the floor joists rest on it and on the walls. A girder that sags or has split shows up above as a floor that dips along a line, and joists that have lost their bearing show up as bounce.
Sill plates and stem walls
The sill plate is the wood laid on top of the concrete stem wall that the house framing sits on. When it stays damp it can darken and soften. The condition of the sill matters twice: for the floor above and for how well the house is tied to the foundation.
Floors that sag or bounce
From above, a post and beam problem looks like a hump or dip in the floor, a door that rubs, a gap at a baseboard or a bounce near the middle of the house. From below it can look like a post out of plumb, a girder with a visible bow, daylight at the sill or a pier block that has cracked.
These signs overlap with settlement of the foundation itself, so the first visit goes under the house and compares the supports with the walls. The page on foundation settlement and piering covers the other case.
Wood and moisture
Wood that stays wet gets infected by decay fungi, a Forest Service manual explains, and the fungi cut its weight and strength. Under a floor, that makes the wet spot the thing to track down, with the soft timber a symptom.
Per Building America, the main moisture source in a vented crawlspace is bulk water: grading, perimeter drainage and gutters. It also recommends a sealed heavy polyethylene ground cover, vented or not. Ground cover cannot hold back standing water, which is why foundation drainage comes first.
Working in a low crawlspace
Access decides much of the job: the size of the hatch, the clearance under the joists and how far the work is from the opening. Material is carried in by hand, and the floor above is supported temporarily while a post or pad is changed.
There is no stock method for a rotted sill plate. The extent of the rot is looked at on site, and an engineer is asked when it affects how the house is carried.
What changes the cost
Price follows the number of posts, pads and beams involved, the length of sill or girder that has to be dealt with and how hard the space is to work in. Moisture control, an engineer’s review or a permit adds to it. A written quote follows a look under the house.
Walls and permits in Kirkland crawlspaces
Kirkland’s permit page lists adding, removing or relocating walls, whether load-bearing or not, as work that needs a permit. That wording matters for crawlspace work where short cripple walls or framing are changed. Whether a given repair is covered is for the Development Services Center to say.
The page also says exemptions do not apply in steep-slope or other critical areas, so a crawlspace on a sloping lot starts with a call to the city.
Questions and answers
Why does my floor bounce over the crawlspace?
The supports under the floor may have moved, rotted or lost their bearing. A joist span with a failing girder or post under it will flex more. Someone has to look under the house to say which it is.
Can a rotted sill plate be repaired?
It depends on how far the rot goes and how the house is attached to the foundation. The extent is checked on site, and where the rot affects how the house is carried an engineer is brought in.
Does a vapor barrier fix a damp crawlspace?
A ground cover reduces vapor from the soil, but it does not deal with standing water or roof runoff. Where the water comes from is looked at first.
Every service is listed on the Kirkland Foundation Repair home page. Anchoring is a different matter from decay, and it has its own page, seismic retrofit and foundation bolting.
Request a free foundation repair quote
Say how old the house is, how you get into the crawlspace and what you notice upstairs. We'll get back to you soon with an estimate or any questions we have. Estimates are free and there's no obligation.
Call (425) 522-5661