Loft boarding with slight difference

[JakeR]

Hi all,

I have a 60's chalet-style house, the loft of which I want to board properly. There are some boards already down on the ceiling joists, right on top of the insulation.

I went back and forth over loft legs, but now have the idea of adding some new joists over the ceiling joists (but not supported by them), and boarding these.

My thinking is that this way the ceiling joists will not have any additional load, and there will be a nice gap for air circulation below. Should also be able to fit some more insulation down.

The joists would be supported by large beams (don't know proper name) that run down either side of the house, and one down the middle. The outside end of the new joists would be supported by joist hangers, and the middle end would sit on the centre beam of the house, attached and braced with metal brackets.

Hopefully my idea is made clear in the photo attachment.

My main question is will those beams (the outer two seem to support roof. Not sure what the centre one does) be able to take the extra load?

Anything else to consider? Is this a stupid idea? If the beams would take the additional weight, I can imagine people might think this is overkill, but I can live with that!

Thanks for any help

Jake

 

[johnny2007]

In theory you will need to ask a structural engineer to check if the supporting beams would be sufficient to support the extra load.
In practice, I have seen this done in hundreds of properties without any ill effect.
The eaves beams seem to be lined up with the external wall, so there should be no problem with them.
The centre beam might be an issue.
Is there a supporting wall underneath it?
Does it span all the way without any support on ground floor?

 

[JakeR]

Thanks for your reply, Johnny.

The eaves beams are actually not above the outside walls, because of the chalet-style construction. Must be roughly where the red dashed line is on below photo.

There is a wall running along the line of the centre beam, both upstairs and down stairs, which also forms one side of the stairway. This wall is broken by one doorway downstairs, and one doorway up stairs. Couldn't say right now whether it is directly below the centre beam, but certainly in general vicinity. Will check when I get home.

 

[johnny2007]

So you need a structural engineer, in theory.
But again, I have seen many lofts done as you suggest without any problem.
That if you just need it for storage.
If you intend to live in it or put something heavy you'll better see a structural engineer.

 

[JakeR]

It'd just be for storage. Much too small and low to live in.