Raising Roof Plate Level

[Brian Ireland]

Hi All,

 

Currently have a 1970's house made of prefabricated concrete panel walls 75mm thick. On top of this is a 75x75mm timber wall plate bolted to top. A truss roof is above this.

 

I want to put in floor insulation and in order to get 2400mm ceiling height in need to raise the ceiling by 120mm.

 

I believe putting a block on the wall isn't really a possibility, therefore, I was thinking of increasing the wall plate level by adding to the wall plate? Any suggestions to this?

 

My thoughts are:

1. Create a beam with 2 number 125x35mm timbers bolted together to create a timber beam 70mm wide by 125mm high

2. Put a 75x125mm timber on top of the existing wall plate

3. Stack a 50x75 and a 75x75mm on top of existing

 

All 3 options would have L-Straps 900mm long fixed to concrete wall

 

I would think in all 3 instances the roof would need to be removed to do this.

 

Interested to hear everyone's thoughts and opinions.

[Russell griffiths]

Are the concrete panels actually the structure, or is there a steel frame and the concrete is just a skin, like the old 1950’s pre fabs. 

[Brian Ireland]

Hi Russell, I don't think they are structural. There is concrete posts at corners or either side of openings and intermediately between bigger spans. Max span between posts is 2850mm. Above the posts and the panels and underneath the wall plate I think there is a concrete ring beam.

It is a Roh-Fab house constructed in Ireland.