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Carpentry & Joinery

Future proof - ceiling joists

Anonymous user 16/03/2024 - 2.43 PM

We are looking to single storey side extension but want to future proof the design so we could easily (and reduce waste) install a second storey. I'm thinking that we design the size of the ceiling joists for the future floor joist. Am I right and thinking that floor joists (first floor) would be larger than what we would need for a flat roof ceiling joist.

Are you a tradesperson and able to answer this question?

4 Answers

Anonymous user

Yes as a rough guide whatever the span of the joist is in feet is the depth of joist that you will require i.e 8ft span = 8 inch deep joist, 10ft span = 10 inch deep joist. Do you see where im going? You will probably struggle to get anything over 12 inches deep. I beams are becoming popular now as they are engineered for specific situatons, they are cheaper and lighter in weight.

Answered1 July 2021

Anonymous user

Get an engineer. You will need his expertise for Building Warrant purposes anyway. I’ve worked with metric sizes for over 40 years and the answer posted here is to say the least a broad brush approach.

Answered3 July 2021

Smithson’s Construction

Rating: 5 out of 5

Barnstaple

Good idea to future proof the joists but most important is to make sure you putting in a strong enough foundation!

Answered4 July 2021

Anonymous user

By installing I beam in centre of room you can reduce size of joist but make sure your i beam is same size as moist as you don’t want beam protruding

Answered19 July 2021