Loft layout baseboard construction

[nev7]

I'm ready to start a loft layout, having ummed and arred for a number of years, and looking for some advice on the baseboard.

What I'm thinking is to span the entire width of the house, across 15'6", using 175 x 22 timber hung on joist hangers fixed to the end walls of the house, to reduce the weight on the floor, possibly with a leg or two in the centre to provide more vertical rigidity. There will be two pairs of parallel joists, approx 10' apart, tied together with more timber towards each end to provide a "roundy-roundy" layout, all topped with 9mm (?) ply.

Has anyone any experience on doing it this way that can point out any likely pitfalls?

And how often would you, wise reader, suggest putting cross members between the parallel joists to support a baseboard width of around 27"?

[Graham108]

Sage advice on this forum is always to consult with a qualified structural engineer

[teaky]

1 hour ago, nev7 said:

I'm ready to start a loft layout, having ummed and arred for a number of years, and looking for some advice on the baseboard.

What I'm thinking is to span the entire width of the house, across 15'6", using 175 x 22 timber hung on joist hangers fixed to the end walls of the house, to reduce the weight on the floor, possibly with a leg or two in the centre to provide more vertical rigidity. There will be two pairs of parallel joists, approx 10' apart, tied together with more timber towards each end to provide a "roundy-roundy" layout, all topped with 9mm (?) ply.

Has anyone any experience on doing it this way that can point out any likely pitfalls?

And how often would you, wise reader, suggest putting cross members between the parallel joists to support a baseboard width of around 27"?

What are you going to stand on to operate the layout?  The ceiling joists?  In most loft spaces these are only designed to support the ceiling, a moderate amount of (well distributed) household storage plus sufficient margin for occasional access.

 

I agree with Graham108's advice but only if you are intending to convert the loft properly.  Unconverted, the loft is probably the least appropriate space in a house for a model railway.  Draughty, dusty, too hot in summer, too cold in winter and difficult to access safely.  Most people would be better off with a shed.

 

Sorry if this is not what you wanted to hear Nev, but you did ask.

 

 

[nev7]

It's already boarded on the joists with 18mm interlocking green board, and at least partially insulated with some of those rudimentary silver foil type rolls.

[ikcdab]

2 hours ago, teaky said:

Unconverted, the loft is probably the least appropriate space in a house for a model railway.  Draughty, dusty, too hot in summer, too cold in winter and difficult to access safely.  Most people would be better off with a shed.

Some people don't have a choice and for a model railway you don't need a full loft conversion.  But you do need to satisfy the insulation question because it will be boiling in summer and freezing in winter.

That aside, it seems like you are fully aware of the issues and you are building your baseboards taking load into account.  I can't visualise what you are intending from your description, can you post a quick diagram?

[chris p bacon]

4 hours ago, nev7 said:

What I'm thinking is to span the entire width of the house, across 15'6", using 175 x 22 timber hung on joist hangers fixed to the end walls of the house, to reduce the weight on the floor, possibly with a leg or two in the centre to provide more vertical rigidity. There will be two pairs of parallel joists, approx 10' apart, tied together with more timber towards each end to provide a "roundy-roundy" layout, all topped with 9mm (?) ply.

Has anyone any experience on doing it this way that can point out any likely pitfalls?

And how often would you, wise reader, suggest putting cross members between the parallel joists to support a baseboard width of around 27"?

 

I won't go into too much detail as I'm not in favour of lofts being used.  The 175 x 22 timber isn't a good idea over such a long span, and by using it to try reducing the weight you intend to put legs in which introduce point loadings onto timbers, which are only intended to hold the ceiling up, rather than support a floor.  

 

4 minutes ago, nev7 said:

It's already boarded on the joists with 18mm interlocking green board, and at least partially insulated with some of those rudimentary silver foil type rolls.

 

There is another problem with what you describe as 'Partially insulated' as without good ventilation the chipboard T&G can trap condensation.

 

3 hours ago, teaky said:

I agree with Graham108's advice but only if you are intending to convert the loft properly.  Unconverted, the loft is probably the least appropriate space in a house for a model railway.  Draughty, dusty, too hot in summer, too cold in winter and difficult to access safely.  Most people would be better off with a shed.

 

^ This.^

 

Lofts are always an issue on here where layouts are concerned as too many say "Ignore the regs", but it's not their house they're making changes to.

 

I do this for a living and have seen too many disasters.

 

[nev7]

Ok, thanks for the input, guys. Will look into other options then

[Wheatley]

Plus one. Apart from anything else it's much harder to fall out of a shed. 

[nev7]

Haven't got room in the yard for any decent sized shed.

Fed up of thinking after years of inaction, and need to be finally doing....

I do have a friend a hundred yards away who is interested in exactly the same time period and the same type of mainly freight operation, but also doesn't have the room for a permanent layout.

Soooo, I guess we'll have to either club together and rent a cheap lockup, or build an dismantle-able (is that even a word?) exhibition layout....