[Bell Historians] Worn out garments show new patches

[Richard Offen]

> Very common, and not an arrangement I like. The same "design 
feature" is
> being proposed at Bushey.
> The problem is that wood is not dimensionally stable as it absorbs
> moisture during wet winter months and no matter how nice and tight 
it is
> sandwiched between metal frame and metal foundation beams, come the
> summer when it bakes dry and shrinks the clamping tension will be 
lost.
> If the beams are oak there is never quite an end to twisting and 
warping
> to add to the problem. 
> There are hundreds of installations built this way and it works well
> enough, but can never be as stable as all steel.
> Maintenance wise you have the corrosion prevention for the steel 
added
> to the need to tighten regularly of wood, the worst of both worlds.
> 

I'm afraid that I don't agree with Rod that such an arrangement of 
timber and steel never works well.   I can think of a great many 
examples where a composite timber and steel foundation has performed 
perfectly adequately for a great many years, with relatively little 
maintenance.

A question for Andrew:   What is gained by retaining the four 
timbers?   

If a new frame is being built, why not build it on a proper double 
layer girder foundation and remove the timber beams altogether?   I 
would have thought that the bother of constructing new framesides 
level and square on a timber foundation would totally negate any cost 
saving gained by retaining the beams ...or perhaps 'level and square' 
isn't considered to be an issue!

R