Q. This week: My house is about 70 years old and the floors on the first story shake when someone walks on them. The problem, I think, is that the floor joists are too narrow. They're only 7.5 ...

If the floor is sagging, old joists can be temporarily propped up with studs or jacks — even bowed into a rise instead of a depression — before sister joists are attached.

Sistering every joist to create one level takes precision. All-new subflooring and flooring is a lot of material to purchase. Finally the fallout of adjusting the trim and stairs takes time and skill.

Q: Our 35-year-old house has a 7-foot cantilevered deck on the top floor -- about 25 feet above ground level. The untreated fir joists feel solid but have large black areas on the sides ...