Home Repair and Paint Guide

... It’s generally stronger and supports more weight than cedar, redwood, or other woods and will last for many years. Pressure treated lumber is rated by pounds of preservative retained per cubic foot of wood. Higher numbers mean greater protection against fungi and insect attack. Matching the rating to intended use will give adequate performance while helping to reduce overall costs. Pressure treated lumber is tagged with the treating solution and concentration that was used during manufacturing. The three common ratings are as follows: Above ground (.15 or .25). Used for the floor, railing, and other topside trim.  Ground-contact (.40). Posts, beams, or other items that will come into contact with the ground, but will never be buried.  Below-grade (.60). Posts and support items that are buried below grade.  When buying cedar or redwood lumber, select boards cut from heartwood. Heartwood contains the natural oils that give these woods their resistance to decay and insect attack. Sapwood (cut from the outer edges of the tree) lacks these oils. If you’re going to use redwood, look for lumber labeled “heartwood common”. This contains more heartwood than “construction common”. Buy wood that’s dry. Lumber that’s still saturated with the water can be twice as heavy as dry wood. It will also shrink when drying. This can cause your deck to have uneven gaps between the boards, and could also shear the screws or loosen nails that hold mounting brackets to joists. If the wood you purchased is wet, let it dry for a few weeks in an area that’s covered and away from direct sunlight. Drying too quickly can lead to warping. Tall decks should be built using 6×6 posts instead of 4×4. They will look better and are more solid. Make sure the posts are straight with no twists, bows, or deep cracks. Remember that the posts have to support the weight of the deck plus people and furniture ...