Bolting Wood Beams Together

While code typically allows 3 8 inch diameter bolts for fastening braces to posts beams or joists i use 1 2 inch diameter bolts instead.

Bolting wood beams together.

The nails will fill the gaps between the hole and bolt to keep it from spinning. Stagger the bolts and make sure the bolts are placed a minimum of 2 1 2 inches from the edge of the beam. Connecting wood beams with through bolts is a safe and easy way to secure two wooden support beams together. When joining pieces of wood together using a carriage bolt the square head on the bolt can become stripped in the hole making them hard to tighten.

To meet this requirement i bolt 2x4s to the posts approximately 2 feet below the bottom of the joists at a 45 degree angle to the beam and joists. Starting about 2 inches from the edges of the beam counterbore two holes on the inside or the least visible side of the beam for carriage bolt nuts. Be on the safe side when in doubt and use extra nails. To solve this problem insert a few finishing nails in the hole beside the bolt before hammering the bolt into place.

An example of a regular bolting pattern might be 1 2 inch diameter or 5 8 inch diameter bolts spaced 16 inches on center. The first method is an empirical method which is purely based on what has worked well in the past. T i ill i l d ti d itopics will include connection design philosophy and behavior an overview of 2015 nds provisions related to bolt design including appendix e for. This course will feature a bolt design example utilizing awc s 2015 national design specification nds for wdc t tiwood construction.

Drill through the beam with a long bit the same diameter as the bolts. Images courtesy of eurocode 5 for example if two 47mm x 195mm are bolted together then m12 bolts should be used and positioned 48mm from the top and bottom and at least 48mm apart vertically if staggered fixings are used.