Creating storage space in the garage roof

[dern]

This is obviously not the greatest picture but it gives an idea of what we have...

roof.jpg (1.09 MiB) Viewed 1579 times

I want to put some of that cheap loft board up in the roof of my garage for storage. The joists are attached to the rafters, and the resulting triangle sits on top of the walls of the garage. The joists hold my weight but deflect. What do I need to do to make this suitable for storing boxes of stuff, some reasonably heavy... boxes of paperwork for example.

[weeksy]

Work fine for me. I've got at a guess 200kg+ up there

[Skub]

Nice ZXR tank.

[dern]

Work fine for me. I've got at a guess 200kg+ up there

We do have stuff up there atm, and it's still there, but given that I want to stick a load more boxes up there, I'm not convinced the strength is there.

More images that are a bit clearer...

roof2.jpg (795.63 KiB) Viewed 1541 times

roof3.jpg (1.25 MiB) Viewed 1541 times

[weeksy]

Same as mine. Same thickness, no issues

[Yorick]

Work fine for me. I've got at a guess 200kg+ up there

We do have stuff up there atm, and it's still there, but given that I want to stick a load more boxes up there, I'm not convinced the strength is there.

You can easily swing off the joists. Probably 100 kilos

Doubt you'd be putting much more onto each beam?

[Skub]

Before I cleared the space in my garage and boarded/insulated it in,there was a lot of stuff up there. Boxes of heavy wood flooring etc. I've no idea of weight,but it took me a day to clear it,with multiple dump runs.

[dern]

Work fine for me. I've got at a guess 200kg+ up there

We do have stuff up there atm, and it's still there, but given that I want to stick a load more boxes up there, I'm not convinced the strength is there.

You can easily swing off the joists. Probably 100 kilos

Doubt you'd be putting much more onto each beam?

I wouldn't have thought so... that would be by far the easiest path, just chucking boards up there I mean.

[Cousin Jack]

if 1 joist will support your weight, say 100 kgs, just make sure your boards span 3 or 4, and don't put anything more than 200 kgs in one place.

[mangocrazy]

You could double up on cross beams if you're still a bit unsure. Looks like you've got wall plates that you could easily fix more cross beams to. That would give more piece of mind, but is probably unnecessary unless you're planning on sticking serious numbers of boxes up there.

[dern]

Thanks all.

[Silly Car]

The best options involve reducing the span of the joists (horizontal sections) as this will reduce them flexing under load, there are plenty options to stiffen them up such as:

Adding strut(s) from the joists to the rafters (pitched roof sections), that way the entire truss it’s carrying the load. It might be worth adding a collar tie (length of 4x2 screwed parallel to the joists) fairly high up from rafters to rafters (helps stop them splaying under loads and add a strut vertically from joist to collar tie

Glue and screw 6” wide strips along length of joists to stiffen them up but you’ll lose some head room

Glue and screw 6 x 2 timbers to one side of each joist, supporting the ends on a ledger plate screwed/bolted to the walls


If it is just about peace of mind, then add extra strength where the heaviest items are going to be stored, such as:

Add gallows brackets / diagonal braces under each end of the joists bolted to the walls

Glue and screw loft boards across the top of the joists, in strips down the length of the garage and distribute the weight evenly

Add gussets ( 18mm ply) cut to brace the intersections between ends of joists and rafters