Using polystyrene sheet

[joshs]

Hi I'm wanting to use polystyrene sheet to raise the level of my layout its just over 2m long and around 40cm wide this is to enable a turntable and inspection pits to be added with out having to cut in to my baseboards as it is a wall mounted layout, so don't want to weaken the structure. My question is there are lots of different types of polystyrene sheeting out there but which is the best and most safe to use bearing in mind that polystyrene is pretty toxic when burning.

Thanks for any help regarding this.

Josh

[TimberSurf]

What thickness is the existing board?
I would NOT use polystyrene, there are a number of materials that are far better, it depend how much you wish to raise the surface. For 3-6mm, cork or closed cell foam would do, if more (12-25mm) then Extruded polystyrene or Phenolic insulation board are readily available at your building merchants.

[joshs]

Hi timbersurf

At the point where the turntable is going it is around 40mm thick but the board is of wafer infill type same as internal wood doors hence why i dont want to start cutting to much out of it.

It needs to be raised at least 35mm which will acomodate the turntable well. i've have a look at Phenolic insulation board thanks for the help.

cheers josh

[Pete]

Hi

Not wishing to disagree with Timbersurf, I guess just different experiences with materials (unless I'm also referring to the extruded polystyrene he mentions) . I buy packs of insulation polystyrene, about £15.00 for a pack of 5, about 1200 x 600 x45mms.

Stick it down with tile cement, not PVA.

As for the fumes, I wouldn't worry, layout fires are very rare... No7 buses are a far greater risk statistically.


Pete

[Bufferstop]

Providing you don't remove too much of the top sheet there's no problem in putting in a turntable pit. Use a trammel type cutter to cut a circle in the top sheet. Lift it out. Cut away the infil. Cut two semicircular walls for the well smother them with wood glue and wangle them in. It might help if you temporarily put a screw in the face of each half circle, so you can push them in far enough to get both in place then pull them back into line. Once in place you can put in some panel pins and remove the screws. I've put holes reinforced in this way into a few similar boards.