Mercer Island homeowners can ask Bellevue Foundation Repair about settling, wall cracks, crawlspace posts and beams, bolting and bracing, and footing drains. It is a drive of about 6 miles from Bellevue.
Mercer Island’s houses are old compared with Bellevue’s. Some 61.3 percent were built before 1980, 39.5 percent of them from 1960 to 1979, and the median home dates from 1973. Add the hillsides and the lake shoreline, and the first questions are about slopes, soil and how the older framing meets the foundation.
Plywood bracing on the short walls of an older crawlspace house
Example project
Home
About 2,000 sq ft house on Mercer Island with a crawlspace
Original request
Bolt and brace the house against an earthquake
Walls
Short walls between the foundation and the floor, in old dark framing
Bracing
New plywood nailed in a regular pattern
Not included
Permit costs and any engineer’s design
Cost
$11,800
In this example, the owners of an older house on Mercer Island have read that bolting and bracing lowers the chance of the house moving off its foundation in an earthquake. The crawlspace has short walls under old, dark framing.
Houses on sloped lots can move for reasons that include the slope. A job in foundation settlement and piering starts with why the ground or footing moved, and on some island lots the city’s hazard rules apply before piers are chosen.
Foundation crack repair
Cracks in a wall mean different things depending on shape, and an old retaining wall or slope can add load to the foundation behind it. Our foundation crack repair page explains tapering, stair-step and horizontal cracks.
Crawlspace post and beam repair
Houses from the 1960s and 1970s may have older crawlspace posts and timber girders. Work in crawlspace post and beam repair starts with what the floor sits on, which is found from under it.
Seismic retrofit and foundation bolting
The island’s older stock is where seismic retrofit and foundation bolting is worth checking, since a house that is not fastened to its foundation can slide in an earthquake. A seismic hazard area adds studies, covered below.
Foundation drainage
Water on a hillside has to go somewhere, and the island’s code has buffers for landslide areas. Plans for foundation drainage near a slope are raised with the city first.
Homes and foundations here
Mercer Island counts about 25,300 residents. One-unit homes make up 67.0 percent of its housing, 10.3 percent of the housing predates 1950, 15.7 percent dates from 1980 to 1999 and 23.0 percent from 2000 on. Owner-occupied homes have a median value of $2 million or more.
Houses of the 1960s and 1970s are the largest group, and a lakeside or hillside lot adds soil and water questions to the age of the house. We say the foundation can only be judged by looking.
Permits and rules to check
Mercer Island’s code designates landslide, seismic and erosion hazard areas, following the state’s guidelines for geologically hazardous areas. Work in a landslide or seismic hazard area, or in its buffer, can require a critical area study. For a seismic hazard site the study includes an evaluation by a qualified professional for seismic engineering and design and the amount of seismic settling that could occur. Whether a given repair is minor enough for the city to waive the study is the code official’s call.
Mercer Island takes part in MyBuildingPermit.com. Its tip sheet on what needs a permit tells owners of property in a critical, shoreline or sensitive area to check with the local jurisdiction. City permit staff can say what your repair needs; permit-free work is not something we promise.
It can. A slope can add soil movement to the causes of a settled foundation, and the city’s critical area rules may apply to work on the lot. Ask the city whether your parcel is in a mapped hazard area.
Is my 1960s house bolted to its foundation?
It may or may not be. Bolts and plates show at the top of the crawlspace wall, and an inspection from under the floor settles it.
Does a repair on the island need a permit?
The city decides. Mercer Island’s code and the regional permit tip sheet both send critical-area properties to the local jurisdiction.
Which part of Mercer Island, how old is the house, and is it on a slope or the shore? Describe what you have seen: a crack, a sloping floor, damp or soft wood. We'll get back to you soon with an estimate or any questions we have. Estimates are free and there's no obligation.
