Installing a beam to support loft inspection path

[fandyman]

Can you get a 4 metre timber up there

By the way how would you then install the 4m beam spanning above the ceiling binder? Would it be directly to the rafters? If so what fixings? What size should the 4m beam be - 2 x 4? The rafters are 2 x 3.

Saying that as I just realised there is a slight chance I can lift the 4m up to loft which I had not realised before.

 

[fandyman]

@Notch7 @cdbe @blup I have now confirmed that I will be able to get 4m timber up to the loft.

What size timber would you advise to place to connect with 2x3 rafters and how would you do it? Also what height from the bottom of the rafter is it ok to install rafter tie?

Some photos below showing the new rafter tie I wanted installing in red:

 

[fandyman]

Should I be using hurricane straps to attach to rafters and 2x6 timber for the rafter tie since it needs to support the weight of an adult?

 

[fandyman]

Any advice greatly appreciated.

Is my idea of attaching 2x6 with these screws four each side ok? Obviously firstly notching the timber at the ends to match the pitch of the roof.

I checked and it looks like the 4m long 2x6 C16 timber is about 20kg in weight so not adding a ton of weight and should be allright.

I am also thinking of raising just very slightly above the ceiling binder (~25mm - just above the heating pipe).

Would I need some noggings to stabilise the connected rafters from flexing?

 

[cdbe]

Your plan seems ok. If you put a block of timber between top of ceiling joists and underside of "tie" beam you won't need to worry about the rafters twisting. What's going on on the right? Is your selected rafter trimmed round a chimney or something - I would check that before hanging anything from it.

 

[fandyman]

@cdbe Many thanks for your advice. It is a chimney indeed. Would I be ok to then move the beam to the next to the left or the the following one as it seems to be passed the chimney there? That would extend the propping points of the path to a distance of 2.0-2.4m but should not change much I suppose.

Question on the overall approach - is the load factor (hanging a floor together with human weight) off two 2x3 rafters on that side (the other is structural wall so I am fine with it) is going to be ok? Just sanity checking as this will be around 120-150kg load I suppose. I am well aware this side of the inspection path will be carrying most of the load as the person inspecting the F&E tank will be standing at the end of the path where the "tie" beam will be supporting it.

 

[Harry Bloomfield]

Any advice greatly appreciated.

Have you considered a walkway, entirely suspended from the roof rafters?

Brackets bolted to the rafters, steel wires hanging, like a V or W from those, more brackets at the bottom holding a horizontal Unistrut, or a timber bearer, a plank on top. Brace the Unistrut/timber, to the ceiling timbers, to prevent swaying. Add some rope handrails, either side.

The loft space, of a certain bank I was once in, included such a walkway, which was frequently made use of, by armed security staff, to gain parapet roof access, when there were visiting dignitaries, at the town hall opposite.

 

[fandyman]

Hmm interesting case.

Can you explain a bit more or point me to a site that shows the solution?

 

[Harry Bloomfield]

Hmm interesting case.

Can you explain a bit more or point me to a site that shows the solution?

Sorry, no - you will have use your imagination.

Suspended walkways seem to be common, in theatre enviroments..

 

[fandyman]

What if I install two ties instead of one in my original setup. I would spread the load more evenly.

 

[cdbe]

Loading the rafters in the position you propose will be fine, I would avoid the trimmed one near the chimney. Your 6x2 is technically under sized for the span but it won't be loaded anywhere near as much as typical floor joist is, your two incoming joists will prevent any twist at mid span if securely connected.

 

[fandyman]

Thanks @cdbe.

Would you use joist hangers or some brackets for the two incoming ones?

 

[cdbe]

Probably something like this, with sheradised nails in all the holes.

 

[fandyman]

I managed to put the beam in position and wonder whether it is too high. It is 12cm above ceiling binder and about 28cm from the bottom of the ceiling joists. The ridge height is 200cm so I reckon this is well within 1/3 of the ridge heigh which I am reading is an absolute must for rafter tie.

The other question now before I fix it in is whether it is not too high for the cross beams to be hung?

Finally I noticed there is the F&E tank that is hung from same rafter but the weight would not be significant as it is just 4 gallon one and mostly half full and even if completely full that would be about 40-50kg max.

 

[fandyman]

@cdbe I might want to as well try and fit a bit longer beam and thus position it lower - I might be able to come down 5-7cm or so.

What do you think?