Loft Problem - Advice

[Barewolf]

Hi Guys N Gals

Ok I am basically going to be boarding my loft, and I want to fit some retractable ladders, but a lot of them say they need a clearance arc of so much room.

My problem is in my loft (See Pics), There's a massive 4inch bearer spanning the width of the two purlins. I can only assume this is to stop the eaves sagging at the base. There's no structural reason for it being there apart from that.

I basically dont like it but i realise that its there for some purpose. If i cut the center of it out, 3ft, and put vertical bearers in, then strengthen the base, would this suffice as an alternative?

The property is a 1960s build. Loft is in very good condition.

[Taf]

Guy up the road did roughly what you suggest. The roof developed a dip in weeks. Expensive to put right with hydraulic jacks and a access hole cut through the roof.

The roofers opened another hatch for him to install the (prebought) ladder set in.

Be careful as some houses in that period used non-standard joist spacings that meant the T&G sheets you can buy won't fit without fitting noggings, etc.

Leave well alone. As Taf said, fixing any problems you might create will be fearsomely expensive. Unless you're competent as a builder/roofer (and clearly you're not), you should confine your DIY to the simplest projects, such as installing boards and ladders that don't impact on anything else in the loft at all.

[heero_yuy]

It might not look it but that is a major triangulation element in the roof structure. It's less common as most site constructed, as opposed to truss, roofs have twin struts to the centre where there is usually a supporting spine wall through the centre of the property. My roof has two sets of these and they support considerable load, you only have to tap them with a hammer to hear that.

I would get the advice of a structural engineer before interfering with it in any way.

[Barewolf]

This is a replica of the loft and what i want to do...

[pip08456]

Originally Posted by Barewolf

This is a replica of the loft and what i want to do...

Which will effectively remove the structurly sound triangulation. You obvviously don't know what you are doing so as above, leave well alone.

[Barewolf]

i dont know what im doing with lofts and roofs, but my dad said he cant see the point in it, and hes been a builder for most of his life.

it looks to me like its to stop the eaves sagging, but thats the only bearer in the loft, and what i suggested to do would easily hold any strain on the purlins surely

Originally Posted by Barewolf

i dont know what im doing with lofts and roofs, but my dad said he cant see the point in it, and hes been a builder for most of his life.

it looks to me like its to stop the eaves sagging, but thats the only bearer in the loft, and what i suggested to do would easily hold any strain on the purlins surely

And yet you're not sure. Even after speaking to your dad.

Seriously: don't. Not without consulting a structural engineer, and definitely not based on the encouragement you're trying to get off random strangers on the internet.

[Taf]

Our house, for example, has an inner wall of insulation blocks that are so flimsy you could push your finger into them. They are not designed to support weight at all. so the purlins do so. Supported at each end by the end walls, and along their length by purlin braces, either diagonals and/or across the width of the roof.



---------- Post added at 17:35 ---------- Previous post was at 17:30 ----------

As heero_yuy said, you only have to tap them with a hammer to hear them "ping" as they are under a large load.

Collar ties often cross from purlin to purlin when the purlin braces are not diagonal but vertical.

In some loft conversions, the purlins are replaced by steel girders, a major expense of the job, but they allow the removal of ties and braces.

[Barewolf]

[/COLOR]As heero_yuy said, you only have to tap them with a hammer to hear them "ping" as they are under a large load.

Collar ties often cross from purlin to purlin when the purlin braces are not diagonal but vertical.

In some loft conversions, the purlins are replaced by steel girders, a major expense of the job, but they allow the removal of ties and braces.

Those purlin bracing is what i am proposing to do in my loft, they distribute any weight along the joists which is effectively what the joist is doing now in the center.

I find it odd there's only one 4x2 joist between the purlins. It doesn't appear to be doing anything significant that couldn't be worked around by distributing the weight down and across the joists, it would basically be the same and evenly distributed.

my Dad seems to thing they could have just put that there to hold the purlins in place while they cemented them in, he doesnt think its anything major.

I asked in the forum incase anyone is a structural engineer, or a builder, that could confirm my theory.

the best thing you have done is ask before blindly ripping timbers out ,i have seen so many disasters and repaired a few .Your roof type is not of the modern prefab type fetched on the back of lorries it is made on site by roofing joiners who did not waste time putting unnecessary timbers in ,every piece does a job .That particular timber is responsible for transferring the weight from the ridge through the supports shown in your other diagrams into the purlins.It would be an easy enough job to move the hatch ,is that not an option ?

[Barewolf]

Originally Posted by martyh

the best thing you have done is ask before blindly ripping timbers out ,i have seen so many disasters and repaired a few .Your roof type is not of the modern prefab type fetched on the back of lorries it is made on site by roofing joiners who did not waste time putting unnecessary timbers in ,every piece does a job .That particular timber is responsible for transferring the weight from the ridge through the supports shown in your other diagrams into the purlins.It would be an easy enough job to move the hatch ,is that not an option ?

No room in the hall to move the hatch, and even if i did i would still have a beam running the width of the loft which you have to step over at waist height.

My neighbour is a gas engineer, hes popping round tomorrow and hes converted his loft, exact same layout, so i will ask him what he did.

Pretty sure though that 4 angled 3x2 from both purlins down to the joists would do the same job if not more than that single beam. But thats just me and common sense. i aint paying £300 for a structural engineer to take one look at it and say it serves no purpose.

Thats your choice of course, but if you do cause expensive damage, chances are your house insurance will not cover it.

[Bulky]

You'll be fine just removing it and doing as you have drawn.

[pip08456]

Originally Posted by Bulky

You'll be fine just removing it and doing as you have drawn.

Are you accepting liability along with your advice?