Sagging Floor Evaluation in Northeast Portland
The foursquare plan concentrates its floor loads in a particular way: a nearly square footprint with a central stair and, usually, a single central bearing line running through the house. Everything depends on that line and on the posts under it in the basement or crawl space.
Where floors slope in these houses, the cause is very often at one of those posts rather than in the joists. A post base that has decayed in a damp crawl space, or a post bearing on a pad that has settled, drops the girder and takes the centre of every floor above it down together. The signature is a house that dishes toward its middle rather than sloping in one direction.
The other Northeast pattern is the third floor. These houses have full attic storeys that get converted, and the framing under a foursquare attic was sized as a ceiling. Adding a bedroom up there increases the load on that same central line, which is frequently how a long-stable house starts moving decades after it was built.
What We Look At Here
- Floor elevations across each storey to establish whether the house dishes centrally
- Central girder and the posts beneath it, particularly post base condition and bearing
- Attic or third-floor conversion framing against actual occupancy loads
- Whether a conversion added load to the central bearing line without adding support
- Joist size, species and span against how each floor is now used
- Deflection separated into long-settled creep and recent movement
More on the service itself: Sagging Floor & Framing Evaluation. More on the area: Northeast Portland.
Questions
Frequently Asked Questions
My Northeast Portland foursquare floors slope toward the middle. What causes that?
Usually the central bearing line — a decayed or settled post under the main girder drops the middle of every floor above it at once. That central dishing pattern points below the house rather than at the joists.