Original stairs badly damaged, would you repair? If yes how?

[Vicky1983]

Hi All,

~1905 staircase is creaking a lot so we removed lath plaster to access underside and work. We discovered extensive woodworm damage, particularly on the stringer against the brickwall. It may be because it is directly above the damp coal cellar and thus bound to keep happening, we're unsure and are currently monitoring to check if active and have ordered moisture meter.

There are three rafters all along the stairs, they could possibly be original, and may have been there to act as a safety structure and or to attach the lath plaster we had to remove to access. The stringer near the brickwall we believe has collapsed in the middle, it is crumbling, split, wedges have fallen, we can push and split with thumbs. The "going" planks of the steps on that side are now all resting on the rafter. Whilst in the middle and on the other side (which is fine and wedges still glued in) the steps do not touch the rafter.

The question is how to repair this? Replacing that stringer would require to dismantle the whole staircase in which case we would simply put new stairs in. We thought of adding a long steel plate between the wall and the stringer however there is only 0.5cm between the wall and the stringer, and it could be a cold spot bringing more moisture. Having a long rafter under the stringer to support from under is also not possible as the stringer was very shallow and effectively each "going" plank is protruding further than the stringer, thus the supporting batten would hit the "going" planks and not being flush with the underside of the stringer.

We're now wondering if we could use the rafter on which the "going" planks are resting (due to stringer failing we believe) as the new structural element (effectively the new stringer). For this would could screw under each step a plank of wood as shown in the photo. However we don't know if this is acceptable or a bad idea. I was able to suspend myself to one of the rafter it seems solid enough, but we also want to do the right thing.

To complicate things, should we want to bring new stairs in, the clearance between the pitch and the upstairs joist / plaster on the way to the first floor is only 1.85m and new regulation requires 2m, hence we don't know how we would work around this should we decide to go for a new staircase (which at this stage, is very much a possibility).

Very keen to listen to your ideas and advices so we can find a way forward to either restore or replace.

Thanks!

 

[Gothichome]

I see no reason why your blocking idea wouldn’t work. Anchor your blocking with some good sturdy fasteners. Not sure of reg’s but most repairs are grandfatherd. Replacement stairs may also be. First off check that the woodworm issue has ceased or they will make short order of your new blocking.

 

[paulc]

To complicate things, should we want to bring new stairs in, the clearance between the pitch and the upstairs joist / plaster on the way to the first floor is only 1.85m and new regulation requires 2m, hence we don't know how we would work around this should we decide to go for a new staircase (which at this stage, is very much a possibility).

The approved documents often referred to as "Building Regulations" clearly state that it is guidance to achieving compliance with legislation. Much of the documents are littered with the word "should" (i.e. advisory), and rarely is the word "must" (mandatory) used. In some places, it uses the phrase "where practical", so worth picking over the sections that you think applies.
That said, the regulations are fairly relaxed when it comes to refurbishment of an existing property, and much of it doesn't apply if you are just making repairs. Whilst it would be stretching interpretation to claim that replacing a staircase is a repair, if current headroom is only 1.85m, increasing it to 2m is likely to be impractical.

 

[Cubist]

I believe I have several times before recounted the tale of our removing a carpet from a short flight of stairs here shortly after moving in, only to find that it was only the carpet itself plus the good graces of extremely sociable woodworm larvae holding the damn thing up! My rather rapid temporary repairs at the time consisted of a few strategically placed short planks and timber props to make the stairs safe while we continued our occupation of the upper floors. When time permitted, gratefully only a few weeks later, the props and planks were removed to be replaced with a solution similar to yours. The only essential difference being that I shaped the blocks to maximise the amount of timber that would ultimately be screwed to the face of what you are calling rafters whilst also ensuring that I maximised the amount of material that would meet the faces of the riser and tread immediately above each block - they're still in place 14 years later - but only because I lost a battle with our local CO about my proposals for a new replacement stair.

One point I would make though is that you should perhaps use a pressure treated timber for your blocks as this seems to combat future infestation. However, I would also ask how those 'rafters' are supported at their foot?