Mid-level tie removal/moving

[friendlyviolinist]

Hi all, would really appreciate advice on the following. I'm in Devon helping my mum create more storage space by boarding the attic of her 1950s semidetached bungalow. Desperately trying to figure out if I can move or remove these horizontal ties/bars (the lower ones pictured), as once I commit to flooring on loft legs, they'll make moving around in the attic a nightmare. The central supports dont go onto to any walls. It looks like we have collar ties already in upper third and joists are parallel to rafters. I'd hope that was sufficient and maybe these additional ones were used in construction only?

 

[Deluks]

I wouldn't risk that, get advice from a structural engineer, additional timber elsewhere will probably be required.

What's going on behind the camera, hipped roof?

Re-read the last line of your question!

If they were built during construction there must be a reason for it, and if subsequently removed, what would then carry out the function that they were performing?

 

[friendlyviolinist]

Hi Deluks, thanks for your advice. From what I've read it seems roof constructions need to be tied at the rafter level which is commonly done by joists. I wondered if during the building process the builders had put these in to hold the frame together whilst putting the joists in, and subsequently the joists (and collar ties further up) perform their role? Hence my last sentence. I've added a couple more photos showing the roof construction.

 

[Deluks]

There's more to it than just ties. The concern I would have, is that the weight of the roof structure including tiles, would cause the lower two thirds of the roof to push inwards, causing what's known as 'dishing' ie: the outside of the roof would become concave.

It appears you have two gable ends, if the lower purlin which spans from end to end was upgraded to a larger section, you may then be able to remove the front to back support strut.
It may require a steel section, ply box or flitch beam. In any case, you'll need a structural engineer to work it out for you. If it bothers you that much then spend the few hundred quid for advice and a simple solution could be found.

The cheaper option is lots of foam padding and duct tape, or a bicycle helmet.