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Underlay or gravel

Posted: Fri Jan 04, 2019 12:31 pm
by GWR
Hi I need some advice. When I come to lay my track on wooden boards do I use roofing felt before laying the track or do I lay the track and just ballast it. One more question if I use roofing felt do I fix it down with adhesive or felt nails. :scratch:

Re: Underlay or gravel

Posted: Fri Jan 04, 2019 12:40 pm
by philipy
I have used roofing felt everywhere, fixed with galvanised clout nails. I did use adhesive at the joints originally to try to prevent water creeping under, but decided that it was pointless when I was going to screw through felt when fixing the track. No reason not to use felt adhesive instead of nails, apart from cost and messiness!

Ballast on top of the felt. I fixed the ballast using cement powder ( A Rowlands type mix) and also SBR bonding agent. I think the SBR is better - just search SBR on this forum and you'll find several references.

Re: Underlay or gravel

Posted: Fri Jan 04, 2019 12:50 pm
by GWR
Hi Philip thanks for the information, really helpful. :thumbleft:

Re: Underlay or gravel

Posted: Fri Jan 04, 2019 2:35 pm
by BorisSpencer
My track bed is all made from reclaimed decking boards, at the outset I considered whether to cover these with roofing felt but in the end decided against.

My reasoning was that if any moisture got under the felt then it would be held against the wood and accelerate its decay, this would also happen out of sight and so may only manifest itself as a sudden catastrophic failure. With the boards uncovered I can see what is going on and retreat, or even replace sections as and when required, with minimal fuss and effort.

This is posted is merely as opinion, rule 1 (it's your railway).

I haven't yet ballasted any areas but this year will be experimenting with Rowlands mix and\or SBR around the more scenic areas of the line.

Re: Underlay or gravel

Posted: Fri Jan 04, 2019 3:23 pm
by GWR
Hi BorisSpencer another informative response. I was thinking about moisture getting in without knowing. :thumbleft:

Re: Underlay or gravel

Posted: Fri Jan 04, 2019 3:34 pm
by Peter Butler
Where boards join, particularly along their length, there will inevitably be expansion and contraction as they get wet and dry out. This is where it is useful to have felt so that the ballast doesn't separate and show straight lines.

Re: Underlay or gravel

Posted: Fri Jan 04, 2019 4:26 pm
by GWR
Peter Butler wrote: Fri Jan 04, 2019 3:34 pm Where boards join, particularly along their length, there will inevitably be expansion and contraction as they get wet and dry out. This is where it is useful to have felt so that the ballast doesn't separate and show straight lines.
Peter thanks for your reply most useful. :thumbleft: