Tongue and groove loft board - how to strenghten rafters?

[greenmug]

Hi
Wonder if you can help?

I'm about to board a small part of my loft, having bought 5 packs of tongue and groove board from my local DIY store (chipboard)

I intended to use the area to store some old books and magazines, and therefore want to improve/strenghten the joists/rafters before doing so.

- The house was built in 1986 and has regular ‘W’ type frames supporting the roof and ceilings, spaced every 600 mm.
- The house is approx 7.5 m front to back. There are no load bearing walls upstairs, just regular stud work.
- The rafters are 32 mm x 70 mm.
- The reach between the lower points of the ‘W’ is 2.1 m.
- There is a water tank on a shelf in the loft above the tank cupboard.

I had hoped I could board the area near the loft hach up to the wall which if you look left once in the hatch is 3 W's to the wall. I was then going to do one board the other side, giving approx 2.4m worth of floor space.

If I want to store some heavy stuff how should I go about strenghtening the floor, can I simply sister up the current rafters with some additional wood using some nuts and bolts? If so, hat type are best?

- Does the sistered wood have to run the full length of the house (front to back) or can I put it up in parts?

thanks for any help. Ive had a look around the web but can't find any guidance on how to do this specifically.

 

[masona]

Are they gang nail roof trusses as below?

You'll need to find where the upright studwork top wallplate is, then cut a square hole from the plasterboard to the wallplate, pack it with square plywood so it past the plasterboard thickness then you can rest the joists on top of the packing so it will clear the plasterboard and the joists will be on the bearing wall and not on the roof trusses

 

[greenmug]

thanks for the info. this is exactly what I was after.