Some older Poway houses sit right on a slab. Others sit up off the dirt on a raised wood floor, with a crawl space underneath and a little hatch somewhere in a closet or on the side of the house.
If yours is the second kind, this post is for you. It’s not about earthquake bolts. We covered those in our post on seismic basics for raised homes. This one is about everything else down there that holds your floor flat.
Who has one
Poway’s housing is older than people expect. Census estimates from the ACS 2024 five-year survey count about 16,936 homes in the city. Roughly 9,400 of them, a little over half, were built before 1980.
The City itself didn’t exist until it incorporated in December 1980, according to its history page. That means the original permits for most of those older homes came from the County, not the City.
Not every pre-1980 house is raised. Plenty are slab. But the older the house, the better the odds there’s a crawl space under at least part of it, especially on sloping lots where the floor had to stay level while the ground dropped away.
How the floor carries weight
Think of it as a chain, top to bottom:
- Floor sheathing and joists. Boards or plywood on top of closely spaced joists.
- Girders. Heavier beams the joists rest on, running across the middle of the house.
- Posts. Short vertical members holding up the girders.
- Piers. Concrete blocks or pads under each post.
- Perimeter foundation. The concrete stem wall around the outside, sometimes with short wood walls on top.
- Soil. What everything finally rests on.
The California Residential Mitigation Program describes the perimeter part well. A raised floor may sit directly on concrete stem walls, on short wood-framed “cripple walls” on top of the concrete, or on a mix of both.
When the floor above sags, bounces or slopes, one of those six links is usually the reason.
Piers and posts
This is where most interior trouble starts.
What we see in older homes:
- Posts that have shifted off their piers.
- Piers that have sunk or tipped in soft or wet soil.
- Shims stacked up over the years, some loose or split.
- Posts that are wood straight on dirt.
- Extra posts someone added after a floor got bouncy, set on a paver or nothing at all.
The state residential code, in Section R304.1, lists places where wood has to be naturally durable or preservative-treated because it’s close to the ground. That includes wood joists closer than 18 inches to exposed ground, wood girders closer than 12 inches, and wood columns closer than 8 inches. Older crawl spaces often have untreated wood well inside those distances.
Girders and joists
Girders are the backbone. When a girder sags, you’ll often feel a dip running the length of the house.
What to check:
- Splits or long cracks along the grain.
- Ends that sit on too little bearing at the stem wall.
- Notches or holes cut for plumbing over the years.
- Joists cut for a drain line and never reinforced.
- Signs of decay or insect damage near bathrooms and kitchens.
Plumbing is a big one. Every remodel since the house was built may have sent someone into the crawl space with a saw.
The ground under it
Poway soil changes block to block. Some lots sit on granite that weathered to sand. Others sit on clay or on fill placed when the tract was graded.
Under a raised floor, the soil only touches the piers and the perimeter. So soil trouble shows up as a single pier dropping, or one side of the house settling, rather than a slab cracking.
Water is the usual trigger. Look for:
- Damp or muddy soil under bathrooms.
- Water stains on the stem wall from outside drainage.
- Standing water after a storm.
- Efflorescence, the white crust, on the concrete.
If water collects under the house, fix where it’s coming from first. Our post on retaining wall drainage covers how water moves around a sloped lot.
Air and access
A crawl space needs air and a way in.
Section R408.2 of the residential code calls for ventilation openings in the perimeter walls. It sets one square foot of opening for each 150 square feet of under-floor area, with one opening within three feet of each corner and covers like corrosion-resistant mesh with openings no bigger than a quarter inch. Section R408.4 calls for an access opening of at least 18 by 24 inches through the floor, or 16 by 24 inches through a perimeter wall.
In older homes, vents get blocked by planters, soil or stored stuff. Access hatches get buried under carpet. Neither helps the wood down there last.
What you’ll notice upstairs
The floor tells you a lot:
- Bouncy spots. Often a missing or loose post, or an undersized joist.
- A dip down the middle. Often a girder sagging or posts settling.
- A slope toward one wall. Could be the perimeter or the soil on that side.
- Squeaks that get worse. Often loose sheathing or shrinking wood.
- Doors that rub. Can follow any of the above.
Our post on sloping floors goes deeper on reading floor movement.
What a careful evaluation looks at
A good crawl-space evaluation should, at minimum:
- Map every post and pier, and note which are loose, tipped or on dirt.
- Note girder and joist condition, including cuts and decay.
- Take floor level readings upstairs.
- Check vents, access and moisture.
- Look at the perimeter stem wall for cracks and settlement.
- Note anything that’s beyond repair and needs design.
When the findings point to structural design, new footings or a foundation change, we coordinate with licensed engineers as needed. Permits run through the City of Poway’s Building Services for work that needs one.
Repair options in plain terms
Common fixes, small to large:
- Reset or replace loose posts on proper piers.
- Add new piers and posts where spans are too long.
- Sister or add support under cut or cracked joists.
- Shore and repair or replace a sagging girder.
- Correct drainage and ventilation.
- Address perimeter foundation movement, which can be a bigger job.
What’s right depends on what’s found. A good scope starts with what’s actually down there, not what’s assumed.
Factors that size a crawl-space job
No prices here. These factors move the size of the job:
- crawl space height and how hard it is to work in
- number of posts and piers that need attention
- girder and joist damage
- soil and moisture conditions
- whether the perimeter foundation is moving
- whether plans and permits are needed
- access around the house, including slopes
Before you close the hatch
A raised floor is a system. When one part gives, the floor tells you. Open the hatch, look with a flashlight, and take photos.
See our raised foundation repair, foundation inspection and sloping floors pages for more. If your floor has started to dip or bounce, request a Free Quote. We serve the whole city of Poway.