The trouble with roofs!

[Mrs F Controller]

Having triumphed over the making of St Thomas Chapel I got all cocky and left it outside this winter, mainly because I couldn't actually get into the shed!
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The roof was made by glueing plastic sheets of 'corrugated iron' to wood. I did this with an exterior silicone sealant which seems to have worked very well in other parts of the railway. So the other day I went for an inspection and to my horror discovered part of the roof had blown off and the silicon just peeled away.

Has anyone got a solution to this as although I love the look if the polystyrene sheets for buildings such as brickwork etc I can never get then to stick properly. I had the same problem with the water tower I did, brickwork over wood and ended up pinning it on with track pins! Not a great finish.

[FBGR]

I've had similar problems in the past.

The solution I adopted was to make the whole structures out of plastic.

JOhn

[Mrs F Controller]

hmm trouble is with big buildings would it be strong enough? Do you use really thick plasticard? I tend to use marine ply for the basic shape because I don't really want to have to bring it in. I am not convinced that an all plasticard building would be sturdy enough and heavy enough to stand the rigours of our wildlife visitors and English weather!

[Narrow Minded]

I tend to use lots of UHU (I forget how much I pay for it at the pound shop ) and make sure I totally seal exposed edges/ridges etc. It seems to retain its "elasticity" for ages - not forever, but long enough between general repairs and spruce ups.
I believe Tag discovered the same qualities in use on the L&W (Shameles endorcement)

[FBGR]

For my fence buildings I used 1.0 mm (40 thou) thick plasticard, braced with 1.0 mm thick stiffeners 20 or 25 mm deep positioned vertically and horizontally in line with the outsides of the openings. The basic roof structures were from 1 mm thick sheet, stiffened every 40 to 50 mm.

For the retaining wall below the buildings, I used similar construction. With these items just hanging/leaning on the fence this appears to be strong enough, especially as the added details help to stiffen the structures.

The shed that I made last summer, being an independent structure, I made a bit stronger by using 1.5 mm (60 thou) thick plasticard, braced with 1.5 mm thick 25 mm deep stiffeners. The roof structure is only 1.0 mm thick, suitably braced and stiffened, and the layer of slates (each one separate) do help to strengthen this. The 'bricks' are only 0.5 mm thick, but the 'timber' is 0.75 or 1.0 mm thick, and the external piers are only made of 1.0 mm thick, but these all add to the stiffening/strengthening.

This is the shed I made last summer, which is strong enough to lean on:

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I have an even larger independent building now under construction, and I am confident enough to use a similar construction.

JOhn

[Peter Butler]

Mrs F Controller, your adhesive problem is one often encountered by those who misinterpret the use of silicone! It appears flexible even when set but looses its adhesive properties when water seeps between the surfaces.
I have often come across repairs by caravan owners who think silicone will prevent water ingress through seals or punctures in caravan sides etc....Not so!!
There is a solution develloped by the trade...GEOBOND or similar, ask at any caravan store or on line. This is in a tube similar to silicone and applied the same way. When 'set' it remains flexible but sticks to the surfaces permanently!
Hope this is the answer to your problem.

[Mrs F Controller]

Thanks to everyone who helped out with the problem I will certainly be trying the UHU for existing problematical buildings and fancy a go with making the pub in plasticard although I have found the 'stone rendered' church has stood the weather very well even if its roof didn't! So may have to do a very old pub!
Thanks again.