Doubling Up Every Other Floor Joist

To achieve this doubling effect in strength and stiffness you will indeed need to gusset the upper and lower joists together.

Doubling up every other floor joist.

Each joist is strong enough to support my weight 175lbs concentrated in a 1 segment of the joist and. If you double those joists you can span 12 feet 3 inches. Not even a 12 micro will span that far. After several centuries of service floor joists in older homes may sag or crack.

The main reason for doubling up floor joists is to double the strength of a single floor joist. 2x4 s actual size spaced 16 on center running the width of the building uninterrupted with the ends resting on top of the wall top plate. I don t think doubling up a 16 2x8 will all of a sudden span 30. How to make floor joists stronger.

I d like to double my ceiling joists to make my attic space easier to work in for electrical plumbing and for lightweight storage. What are they and why use them. Double floor joists are two joists side by side that are usually nailed or screwed together along the length. I need to put two large velux roof lights 1200 x 1500 in line with each other which means removing two joists and trimming around them.

If we use strong enough gussets and fasteners we know that the top and bottom joists will deflect by exactly the same amount when loaded. I would think the doubled up s would span further because you can attach one to the other more thoroughly. Long spans of joists in newer homes may wobble or bounce from foot traffic. Why would you use a double floor joist.

Therefore following static s advice about doubled up strength if i double up all the c24 47x170 joists to make 94x170 it seems that they should be more than adequate.