Can I remove my ceiling joists?

[keilo]

Hello,

My house is mid terrace. I am going to change the bedroom ceiling joists, to building regs joists 75x195's, in order to convert my loft space. I have read that I should replace each joist one by one to keep the structure of the house safe. But does this apply to mid terrace houses too?

The roof is supported by 2 purlins that are supported in both party walls.

Could I remove all the old ceiling joists, without the house falling down?

 

[noseall]

Replace them one at a time otherwise you could have the bottom. springing out and upwards leading to the roof losing shape.

Granted, there may be a purlin there adding to the strength of the roof but it may have to bear too much stress if you try and hit them all in one go.

A modern, not so tired roof may stand it but i would not risk a full loaded roof at any price.

Why the reluctance to do them piecemeal?

 

[^woody^]

Why do you need to replace them .... why not just put the new joists next to to the existing ones?

 

[keilo]

Granted, there may be a purlin there adding to the strength of the roof but it may have to bear too much stress if you try and hit them all in one go.

Thats good enough for me, thanks for the advice. I am planning on lowering the ceiling by a course of brick, and wasn't sure if the original joists, had much structural use, as they are only holding the ceiling up, and they're rather thin and bowed. I will do them one at a time

 

[OwainDIYer]

wasn't sure if the original joists, had much structural use, as they are only holding the ceiling up, and they're rather thin and bowed. I will do them one at a time

They're also, in tension, stopping the base of the roof triangle spreading out, the ridge of the roof collapsing, and your house walls being pushed outwards.

You can probably replace them in batches if you use additional temporary bracing but your structural engineer would have to design and certify a safe method of work.

 

[^woody^]

I still cant see the need to remove the existing.

As per above, the joists tie the roof rafters and prevent spread of the roof and external walls, so in fitting any new joists they need to be tied to the rafters to perform this function too ... if that can't be done then the existing ones need to stay in