Baseboard construction

[Robin DL]

I have a raised station area, 18ft by 2ft, constructed of 18mm ply (supported by three longitudinal beams) covered in roof felt. It has lasted 25 odd years but now needs replacing. Last time I used marine ply but that is now almost £200 for an 8 x 4ft sheet (and I need two), so the obvious question, what else could I use?

Standard ply is about £35 a sheet so if I cover it better than I did last time would that last OK? Or are there any other materials now available that could be used?

[Sturminster_Newton]

Rule 1 of outside work DO NOT SKIMP ON QUALITY unless your railway is in the Atacama or Antartica both have famously low ambient humidity levels but also some other environment tricks which make them less than ideal.

 

You will need W.B.P. (Water Boil Proof) ply grades and that supplied will not be as long lasting as that you are replacing.

 

Modern stuff seems to rot before you get through the fifth winter and it is touch and go whether in a horizontal orientation it will see out 10-15 years...The stuff used for house building is always at a fairly steep angle to the horizontal so has a better service life. All are only waterproof where they are not punctured by fixings.

 

There are alternatives such as orientated strand board (OSB) which can be purchased in a waterproof grade for shower backing in the bathroom. try >> Abacus Elements Waterproof Wall Kit 3 12mm - 7.20sqm << in google.

 

There is also waterproof MDF but either board will be almost as expensive as the WBP ply.

 

I built with belt and braces using commercial 900 x 600 x 50mm paving slabs mounted on 3m concrete beans with a 150mm reinforced concrete base, this provides a base that will last pretty much until the house is no more but may be a bit over engineered. It also survives the best/worst that West Contry weather and a woodland environment can produce.

 

The left field choice would be recycled plastic and stainless steel screws. It cuts using wood tools and will last - it will also be lighter than the ply and need less foundation than concrete blocks topped with concrete beams and paving slabs.

 

Spend wisely, spend once.

Edited March 23 by Sturminster_Newton
improve readability

[Nearholmer]

Google ‘Filcris’.

 

They supply very good boards and sections made from recycled plastic, mostly for parks and gardens, but they have a specific range of bits for outdoor railway modelling.

[Stray]

 

 

This is a section of baseboard that I haven't used, it's 12mm ply on a frame of treated fence rail. It had a couple of coats of wood preservative, the felt was stuck on with bitumen felt adhesive and held in place with galvanised staples. It's been laid behind the shed for the last 4 years and is showing no signs of any rot or damage.

I reckon the bottom of the treated timber posts and metal spikes will go first, and they're usually good for 20 years. 

I also used some 6mm plywood coated in yacht varnish for a station platform, it lasted about 2 years. 

 

It's all about exposure, plywood will last a long time if you can keep the elements out. 

 

Edited March 24 by Stray

[Nearholmer]

A good option if you want to stick with a generally wooden form of construction is to use concrete “spur posts”. These are short posts, to which wooden posts are bolted so that they are clear of the soil. I did all of our (tall, and long, heavy panels) garden fence with them, and that has survived unscathed, while our neighbour’s, done at the same time, came down last year due to rotted posts and cost him a fortune to have rebuilt.

 

For plywood away from the soil, yacht varnish is incredibly durable too. On a former line I made a long girder (8ft) to cross an area where I didn’t want posts, using 2x1 softwood and ply to make an I-box, which I then gave three coats of yacht varnish (first one let down 50:50), and that shrugged-off the rain and damp.

 

Soil and stagnant air are the enemies of wood, because the one is full of cellulose recyling bugs, and the other encourages them to take up residence.