How to install flooring for storage in roof space?

[Matkai]

We’re in the process of having an attic ladder installed and are considering DIYing some flooring in the roof space for storage. The average cost to have particle board installed by the same company doing the ladder is around $130 per square meter. Since we need about 15 square meters, we think we can do it more affordably ourselves. Additionally, we are concerned about using particle board or mdf as flooring as we get some water in our roof space during storms because our clay roof tiles don’t have sarking. This water has always evaporated quickly and hasn't caused any ceiling issues in over 23 years.

Apologies for the long introduction—here's my questions:

Is this an easy DIY job?
What should we keep in mind or consider?

Our thoughts so far  were to use marine-grade plywood (approximately 9mm) for the flooring and adding extra lengths of blue pine (90 x 35mm) across the adjoining walls for additional support. (our roof is constructed of timber)

Any feedback or advice would be appreciated!

[EricL]

Hello @Matkai 

Thanks for sharing your question about using your roof space as storage. Using your roof space is an excellent way to store items. However, safety must be taken into consideration as you would not want any of your items falling through the ceiling frame. Your ceiling frame has been designed to carry its own weight and that of the ceiling plasterboard. 

Adding extra weight to the frame will be going outside of its design limits. I suggest engaging the services of a structural engineer or an experienced builder who's done this type of conversion. In this manner your storage area will be safe and secure. 

I also suggest having a look at these previous discussions on the topic:

• Attic roof storage, walkway and ladder by @Remarka6le 
   
• How to proceed with attic storage? by @mike13

• Loft attic conversion by @zeroasylum

• Flooring suggestions - utility attic space by @deslea

• Attic room conversion by @matty-two-soups.

If you have any other questions we can help with, please let us know.

Eric