Crawling boards - lightweight material?

[David]

This may be the year I get to sort out some issues with the plastic roof. Includes cleaning, but also some flashings and cable runs.

The roof is supported by 5"2s at 42" centres.

Threads in the past have suggested that crawling boards could be the way to go.

Scaffold boards are an obvious option, but they are quite heavy to move around.

Can anyone suggest a strong but much lighter material which could be suitable?

Putting this up here for suggestions before I go away and research. Which usually results in too much information and distractions and little progress.

TIA

Dave R

[Tricky Dicky]

OSB would be my choice for cheap and light but 42” is quite a span and likely bowing would put pressure on the plastic roof. I would look at edging the crawler boards with some edge battening and just check the board can support your weight without bowing.

[David]

Ta.

I have some OSB in stock, and am due some 2x2 and batten for other projects.

I was thinking of something light and strong like GRP but searches so far haven't turned up much.

I would need a minimum of 2 boards so I could stand on one and move the other so as to access the full length of roof. Which implies (rope?) handles as well.

Cheers

Dave R

[Colin Bignell]

You can get them in aluminium.

[alan_m]

On a fairly flatish roof I have used a lightweight ali ladder with some old pillows/cushions/foam tied to the underside.

[Theo]

Not tried it but PIR insulation foam (Celotex etc) say 50-100mm is lightweight but quite rigid. It'll take a dent if you put a lot of pressure on a sharp point, but is quite sturdy if you distribute weight across a large area. If you're worried about pressure, maybe a sheet of hardboard or thin plywood glued to the surface to spread the load.

It's not the cheapest, although you might be able to find pieces out of a skip or something from someone doing renovations.

Theo

[Harry Bloomfield Esq]

Your reinforcing battens, would need to be on the upper face, fixed with screws from the under side of the OSB, to avoid the point loads. A sheet of something like polystyrene, glued to the underside, might help even more with load spreading.

[The Natural Philosopher]

You would be surprised at how strong expanded insulation foam is. I'd get a pack of that. In practice the surface is sufficiently soft to give way under excessive local pressure, so spreading the load pretty well over the boards

[Tim Lamb]

I've used an Aluminium ladder with pads of any foam insulation to hand for access on brittle corrugated asbestos roofing. The scaffold board later laid along the rungs for comfort. No experience of lightweight plastic roofing.

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[Chris Hogg]

I use old floorboards laid across 32" spaced glazing bars when crawling around on the glass roof of my lean-to conservatory to clean out gutters etc. Not particularly wide, so you have to be a bit careful where you put your feet, and they may bow a bit over 42", but they're what I use.