Installing a beam to support loft inspection path

[fandyman]

Since I am considering replacing it I suppose I should redo it with longer 2x6 (C24 instead of C16) timber as 2x8 would be too heavy to be attached to 2x3 rafters. What do you think?

 

[cdbe]

Lower the better (but leave at least 25mm above the binder so it doesn't start pressing onto it if it deflects a bit). I know you're calling it a "tie" but that serves a completely different purpose - yours is just a beam. If you've fixed it in place have a careful bounce mid span and see how it feels - I'm sure it will be fine for the intended use.

 

[fandyman]

Thanks @cdbe for valuable input.

I will position as you say and settled on 2x7 C24 in the end. Hope it does not overload the 2x3 rafters too much with the F&E tank being held up by the same rafters as well (I think it shouldn't as it will be installed very close to the wall plates).

 

[cdbe]

Just found a picture of my loft storage platform which I built as a temporary thing when we first bought the house as we were desperate for storage.

The left hand side was built of the internal wall - the rest is hanging from the purlin and ridge beam - the frame work was 4x2 and had a bit of bounce, it's 200mm above the ceiling joists so as not to compromise the insulation. It was pretty heavily loaded (boxes of laminate flooring etc) but didn't seem to have any affect on the ridge/purlin in the fes years it was there.

 

[fandyman]

Thanks for the photo and the post @cdbe.

Looks very sturdy.

Do you think I should change my plan and hang the inspection path off the purlins? Your purlins look many times as big as mine so unsure. Would it be better to spread the load off purlins rather than off the "rafter tie"? If I am not storing anything there at all - would using the "rafter tie" solution be easier and work as well in my case?

If going with the "off purlins" installation I would have to notch the wood so it fits into them as mine look a bit different to yours I suppose?

 

[fandyman]

Also why only temporary? Did you get rid of it later on?

 

[Harry Bloomfield]

Do you think I should change my plan and hang the inspection path off the purlins?

I would say - certainly. The design of, layout, and general robustness is much easier, better, in your case. There are numerous ways to do it too..

Devise a hanger strap system, which fixes over the purlins. From those brackets, you can use either threaded rod, or steel wires with wire clamps. Hanging from the rods/wires, either walkway wide timbers, or better sections of Unistrut. Across the top of your Unistrut, as the actual walkway, you could use 18" wide cable tray.

Make the hangers come down as a V and it makes it very stable, but add a few side braces, to prevent the walkway swaying side to side, and some ropes as hand rails.

 

[fandyman]

Also why only temporary? Did you get rid of it later on?

@cdbe bumping for a response just for my knowledge. Many thanks

 

[cdbe]

It was temporary because I subsequently replaced the ceiling and the saggy old joists when I gutted the room below. In addition to the Christmas decorations I reckon there's about half a tonne of junk stored up there that my wife insists we need.

 

[fandyman]

Thanks @cdbe. It all makes sense now.

On a slightly different topic since you worked with would a lot - I've just got the C24 2x7 delivered today and it has some splits in it at the ends?

Is this normal and nothing to worry about or can this develop into longer splits as I have not got wood with splits delivered before. I am planning to use the whole length.

If I don't send it back should I use the section that has split or cut it as waste? It is about 20cm each side.

 

[cdbe]

It'll be fine, obviously if you can trim the split part off then do so.

 

[fandyman]

I did install the 7x2 and it worked out pretty well. I was able to kneel and later sit on it in the middle section without any problem although there was slight wobble sideways (I am really glad I went with C24 and 7x2 in the end).

I did, however, damage the roofing felt in the process. Any ideas how to fix a hole in roofing felt? Is flashbanding any good? I have a big enough piece of existing felt but not sure how would I fix it as no access from outside?