Using GRP

[philipy]

I'm currently investigating ways to replace the thatched roof on my little thatched cottage. The current roof was bundles of plumbers hemp soaked in waterproof PVA and has lasted several years before the combined effects of weather and birds destroyed it.
I'm wondering ifa GRP one might be a longer term answer, but I don't want to end up with a smooth glossy top surface, so I'm thinking that:
1) laying a chopped strand mat right on top of the resin might work? The problem is that the fibres will run in all random directions, which is the one thing that real thatch doesn't do.
2) I've found this long strand insulation and I'm wondering if it might be possible to comb it out into moree or less parallel strands and lay that on top? ( Yes I know that glass fibres are nasty and I'd need skin and breathing protection).

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https://www.ebay.co.uk/itm/A-Glass-Long ... 0891458078


I know that there are boat builders etc amongst us, and I wondered if anyone could offer advice on these thoughts or any other suggestions, please?

[LNR]

Sorry Philip, although far more familiar with GRP than I would prefer, I can't see your idea working I'm afraid,(hoping I'm wrong!) as to preserve it all you would have to wet out the glass' and I would imagine it will just become a very low relief surface albeit with straight striations instead of the criss-crossed ones.
I wonder how the plumbers hemp would go. with a coat of polyester resin brushed gently on it. If you were happy with the look of it previously, I'm sure the resin would last longer than the PVA. Just a thought and maybe not a good one.
Grant.

[philipy]

Thanks Grant. I did wonder if it might sink in and disappear, so you've more or less confirmed that (and saved me some money!).

I have also considered encapsulating the hemp, as you suggest, but I suspect that to get it weatherproof I'd actually need to coat it thickly enough to end up with the same effect as glass fibre.

I'm currently wondering if artificial grass bent down flat might be effective. The trouble with that idea is that artificial grass is either poly propylene or nylon as far as I can tell, and I'd then have a painting problem. Unless.... I can overcoat it with a thin layer of resin which might soak in enough to grip but remain thin enough to keep the texture.

[IanC]

Thanks Grant. I did wonder if it might sink in and disappear, so you've more or less confirmed that (and saved me some money!).

I have also considered encapsulating the hemp, as you suggest, but I suspect that to get it weatherproof I'd actually need to coat it thickly enough to end up with the same effect as glass fibre.

I'm currently wondering if artificial grass bent down flat might be effective. The trouble with that idea is that artificial grass is either poly propylene or nylon as far as I can tell, and I'd then have a painting problem. Unless.... I can overcoat it with a thin layer of resin which might soak in enough to grip but remain thin enough to keep the texture.

Pioneering work Philip. The skills, knowledge and ingenuity of members on here never ceases to amaze me

[invicta280]

I too would avoid GRP if at all possible. It is great stuff for the right application but I would stick to natural materials like your hemp. What about waterproof spray, as used on shoes/clothing? Maybe some type of clear grease. Real thatch has to be replaced from time to time.
There is a fencing product called brushwood fencing which is sold in rolls as garden screening. I have some in my garden supplied by Primrose Ltd. They may be able to supply small amounts. It would make great thatch and could be bundled, tied and pinned like the real thing I reckon.

[philipy]

I too would avoid GRP if at all possible. It is great stuff for the right application but I would stick to natural materials like your hemp. What about waterproof spray, as used on shoes/clothing? Maybe some type of clear grease. Real thatch has to be replaced from time to time.

If you look at my original build thread you'll see how much effort the hemp took. It's lasted 4 years at a pinch, but in reality was looking a bit tatty after 2-ish, so I'm looking for something more permanent than that, even if it doesn't look quite as realistic. https://gardenrails.org/forum/viewtopic ... ed+cottage
Spray, grease, etc isn't going to do it I think, if liberal quanities of waterproof PVA broke down.

There is a fencing product called brushwood fencing which is sold in rolls as garden screening. I have some in my garden supplied by Primrose Ltd. They may be able to supply small amounts. It would make great thatch and could be bundled, tied and pinned like the real thing I reckon.

Now that is a thought. I've seen it in garden centres but never paid it much attention before, but I'll take a look. Having said that, I'm still back to the weather proofing problem unless I can soak it in resin or something.
Thansk for the idea though.

[Peter Butler]

Just Julie, of this Forum, has used bristles from a yard broom, laid in layers and overlapped. The effect is decorative (as are some thatched roofs) and could last quite some time outdoors...... possibly? Unsure of the type of adhesive required for outdoor use, but I'm sure someone can offer suggestions.
Perhaps there are stockists of the bristles in longer lengths?

[philipy]

Peter,
Thanks. Julie did post about her roof the last time this subject came up. I'm sure that one of the modern synthetic builders adhesives would do the job. Something like Stixall or one of the Evo products perhaps

[johnto]

Why not try welcome fibre door mats it has been out on a cottage ,3 years now (not the one with welcome on it)

[tom_tom_go]

Why not try welcome fibre door mats it has been out on a cottage ,3 years now (not the one with welcome on it)

That sounds like a good idea?

[invicta280]

Now that is a thought. I've seen it in garden centres but never paid it much attention before, but I'll take a look. Having said that, I'm still back to the weather proofing problem unless I can soak it in resin or something.
Thansk for the idea though.

Some of the brushwood fencing in my garden has been here three years. The fencing itself breaks down over time as the wind and foxes, cats etc cause it to break apart but the fibres seem very weather resistant

[philipy]

Why not try welcome fibre door mats it has been out on a cottage ,3 years now (not the one with welcome on it)

Thanks for the suggestion. In fact yesterday afternoon I ordered samples of various bits and pieces to experiment with and coconut matting was one of them, so we'll see how it goes.

[Lonsdaler]

Peter Jones of Compton fame achieved passable results using faux polyester fur (p.171 of 'Making Model Buildings for Garden railways')
He brushed it vigorously to tame it, and then daubed on polyurethane varnish to hold it down, which also gave it some weather resistance.

[FWLR]

I read the very same article Phil….Great reading.

He also used coconut matting if I recall.

Have a look Phillip, it may inspire you to something the great man did.