Home / Beam & Sill Replacement
The sill plate and main beam are the two pieces of wood every other part of your house rests on. When termites eat through them, they have to be replaced, and the house has to be held up while that happens.
The sill plate (some older Berks County homes have a heavier timber called a sill beam) is the first piece of wood on top of your foundation wall. Floor joists, rim boards, and exterior walls all sit on it. The main beam, also called a girder or carrying beam, runs down the middle of the basement or crawl space and supports the inner ends of the floor joists. Between them, these two members carry most of the first floor and everything above it. Because the sill sits directly on masonry at soil level, it is also the first wood a subterranean termite colony reaches when it climbs the foundation.
Termites travel from the soil up the foundation in mud tubes, often on the inside face of the wall where nobody looks. The top of the wall is where they find food. In many older homes the sill was laid directly on stone or block with no barrier between them, so moisture wicks from the masonry into the wood. Damp, untreated wood at the edge of the soil is exactly what a colony wants. Damage often runs along the sill for several feet before anything shows inside the house.
Many homes around Reading sit on fieldstone or rubble-stone foundations laid with lime mortar. Those walls are uneven on top, they rarely have anchor bolts, and the mortar near the sill is often soft. Replacing a sill on stone means leveling the bearing surface, sometimes repointing the top courses, and choosing an anchoring method that suits the wall. It's slower than replacing a sill on a modern poured or block wall, and it is one reason a sill replacement price varies so much from house to house.
Termite damage on a sill is usually localized to a section of wall, often where a downspout, a leaky hose bib, or soil against the siding kept that area damp. Most jobs replace a section, splicing new treated lumber to sound existing sill at each end. A whole-wall sill replacement happens when damage runs the length of the wall. On a beam, a short damaged section near a post can sometimes be reinforced with a new post or plate, while damage at mid-span or at a bearing usually means a new beam. The assessment decides.
A new sill in the same wet conditions will start the same cycle. We look at grading, downspouts, and soil or mulch against the siding, and point out what needs correcting. If the crawl space or basement is damp, see wood rot and moisture repair and crawl space restoration.
A sill plate is the dimensional board, typically 2x6 or 2x8, on top of a modern foundation. Older homes sometimes have a heavier sill beam or sill timber that does the same job but is a larger, solid piece. Both are replaced the same basic way, though matching an old timber takes more planning.
Yes. The framing is shored just enough to take the load off the sill, usually a fraction of an inch, and the house is never lifted in the way people picture. Sections are replaced one at a time.
It depends on how much section is gone and what it supports. A soft outer face is a monitoring issue. A sill that has lost its core under a bearing wall is a structural problem that should be repaired before it gets worse.
A short section of sill is often a day or two of work. A full main beam or a whole wall of sill takes longer, mostly because of shoring and access. You'll get a timeline with the written scope.
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