Jump to content
 

Shoring up a layout


 Share

Recommended Posts

Hi all, parts of my layout have started to sag a little. Its built out of soft wood frames and chipboard (I know, I know). The board in particular is 8ft x 3.5ft, it has to be that big due to its position. Has anyone successfully straightened up a chip board layout? The board itself is in excellent condition. I thought maybe making a plywood frame with lots of bracing to fit inside the frame that's already there? Stripping the layout and rebuilding isn't an option due to cost and that I've got the track work exactly how I want it after 3 years of trying! Any suggestions would be greatly appreciated. Thanks

Link to post
Share on other sites

Is the chipboard sagging between the supports, or is the entire thing sagging in the middle?

 

If the former, i can’t think of a viable answer, but if the latter you might be able to save it by fitting truss-rods, as per a real carriage/wagon, or ‘fish belly’ stiffeners, but in either case you will need to Jack it up to get it straight before fitting whatever.

 

No chance of fitting a cross pice and legs at the centre point, I suppose?

 

An 8ft span is a long old way for what must be a terribly heavy thing.

Link to post
Share on other sites

Agree entirely with nearhomer. The critical bit of kit is a length of bricklayers twine and some 20 mm pins. Forget lasers, this the only way to find out what is going on. I like the idea of creating an exoskeleton from ply, but given an 8' span would go for 9" depth. A good timber merchant or B&Q will machine cut these to provide the necessary straight edge.

Some recycled 2x2" and scrap plywood beermats will be needed to support the centre until the outer frame is complete

Link to post
Share on other sites

The board is actually removable, the only board that is. It sit over the roof of a stairwell, hence the size. I made it removable so I could access the point motors if needed, so will probably help with strengthening. I do have a couple of small legs in the middle, but they rest on a plasterboard surface, so I doubt that will help the cause

Link to post
Share on other sites

  • RMweb Gold

Over a stairwell you say?  That probably precIudes the use of jacks; you need skyhooks!  I would lift the board out (you say it is designed to do this but I’m glad I don’t have to; get a few big lads in and buy them lots of beer) and build a hefty timber subframe with plenty of cross bracing to lay on to a solid batten in the stairwell wall and another fixed to the balustrade side; the balustrade is not designed for this load and may need extra bracing off the wall.  All of which will compromise headroom in the stairwell. 
 

This subframe basically acts as a false floor to lay the board on.  If the building stays up, you’ve cracked it.  Using space over a stairwell is ingenious, but unsupported chipboard was not the most suitable material and hindsight is a wonderful thing.    Ply on a well built frame would have been better, but it’s too late now.  
 

I would consider replacing the chipboard with ply at some time in the future. 
 

Good luck and let us know how things progress!

Link to post
Share on other sites

On 05/09/2020 at 11:38, Nearholmer said:

Us amateur structural engineers really need a photo or drawing, because I’m envisaging this as being over the boxed-in stairwell, rather than an open stairwell.

It’s boxed in yes. I’ll get a photo up tomorrow 

Link to post
Share on other sites

If that is an eight foot span no wonder it's bowed.  I would be looking at old floorboards, maybe 6" X 1" as supports.    No law says the frame has to be under the baseboard surface, some of mine had the side frames projecting above the surface and I have used 2X1 on its side for bracing disguised as platforms.    

I would look to fit a pair of 8ft X 6" X 1" floorboards alongside the present sideframes with some similar pieces 3ft 6" long crossways in pairs with spacing blocks drilled so you can pass bolts through, down through the baseboard surface and into the framing.  Then tighten the bolts and pull the sagged areas back into line. Might take a few goes, bit at a time.   Pull them more than level and then you can set about inserting some decent supports of wide but thin wood,  Some adjusting wedges would be good.  I have these issues with a softboard / sundela board mis mask of baseboards and even a piece of 9" X 2" solid timber but I can get a screw jack and packing under mine so I don't need the over baseboard "Sky Hooks"

  • Thanks 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...