How to attach a deck to the house
Q: I’m selling my house, which has a deck more than 9 feet off the ground. A home inspector told an interested party that screws holding the deck are not right. He said the deck has to be secured to the posts and that the bolts against the house are in the wrong place. The people did not buy the house and now I’m afraid the word is out and no one will buy my home. Is this something I can fix or do I need a contractor?
A: Securing a deck is easy if you have minor skills and the right equipment. There are two places where the deck is supported off the ground.
Most failures occur at the ledger board because of rot, loose nails, splits in the ledger or improper placement of the supporting bolts. On older homes the ledger board is often simply face-nailed to the house without knowing if the nails are set into the home’s structure or into part of the exterior siding. The same applies for bolts that miss or split the ends of the home’s joists (the joists cannot be seen by the installer).
I sometimes see on newer homes that the bolts have been set when the home is under construction in preparation for the ledger board to be added at a later date. Because the deck is slightly lower, 2 to 4 inches, than the patio door, the bolts only support the top section of the ledger.
Over time the ledger can split where the bolts are only 1 1/2 inches from the top of a 10-inch ledger board. If the bolts were lower, they would support at least 8 inches of the ledger.
With the proper drill, new bolts can be added near the bottom of the ledger. All joists should have a joist hanger at each end of each joist. The hangers are installed using hanger nails. Common nails will cause corrosion and the hangers will eventually fail.
The easiest repair is where the header board is attached to the posts. I normally see four nails or screws supporting the headers to the posts, and this is where the deck could eventually fail. A 3/8 to 1/2-inch lag bolt with washers and a nut set near the bottom of the header are needed at each post for proper support. Simply drill a hole and set the bolts. There is no need to remove the nails.
Planning a new deck? Design the deck so that the header rests on top of the posts for maximum support.