Staircase Installation

by Louise

I have 3 questions about a staircase installation which I hope you can answer so that I can organise which order I need to have work completed in my extension.

1. Should the wall finishing (plastering) be done before a new staircase is installed?

2. Should the upper floor have been laid before the staircase is installed and if not should a floor board be put in at the top of the staircase before the staircase is installed.

3. Roughly how long should it take 2 builders to install a pre-made staircase.

Your help is greatly appreciated!

Comments for Staircase Installation

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Aug 06, 2015
Plaster board
by: Jaime


You mention fit staircase before plaster, do you also mean before plaster boards? Also please what would happen if we wanted to plaster board/ plAster first?


Mar 10, 2012
Staircase installation
by: Gary

Good questions, I should of already included this information in the staircase section of the site!

1: Plastering is done after the staircase is installed. A few reasons, the biggest being that you'll want (and need for 30min fire protection) the underside of the staircase to be plaster-boarded and plastered too - and you don't want them to have to come back for that.

Unless the underside of the staircase is being left open you may also want a storage cupboard built there that again would want plastering.

When the stairs are installed, the string (piece of timber against the wall that the treads are fitted into) will be a guide for the plasterer. He'll keep an even margin from the edge of the string to his plaster and a timber cover strip will be fitted there later like at the bottom of this skirting page.
It shows how I fitted the top part of the skirting board up the staircase to make it seem like the skirting is continuous.
If your second fix carpenter doesn't do that, you'll still need quadrant or some other small moulding there because plaster to timber will always crack as they shrink and expand at different rates. You'll probably have something on your existing staircase they should match it to?

2: The flooring I would probably install first but leave a section out to be fitted after the stairs are in. To be fair that's only from a safety point of view, and might not be practical if you're having t&g pine boards.

If the stairs are installed first the floor can then be laid completely in one hit.

It doesn't matter which order really, so if the stairs are ready get them in but if you're waiting for them to be made or delivered get the floor down to keep the job moving.

The nosing (top tread, only about 60mm deep) and top newel post will sit onto the joist or trimmer and if the floors there it can easily be cut back when the stairs are installed. You can see the drawing on this staircase page that shows the nosing flush with the flooring and how they are sat on a double joist. That example is for the landing not the stairs but the idea is the same.

3: A staircase installation is a two man job because it's heavy. They should easily finish that in a day though. Even if it's a double winder flight and some of the treads are left out to be fitted during the installation.

Mar 10, 2012
by: Gary

If you're having a cupboard they should get that done too. The area is ready, it's just a matter of bringing it in, marking the top post to cut, lifting it in place, levelling, fixing to the joist, floor and wall. Couple of hours. Then batten the back and plasterboard the underside before building the cupboard.
Make sure everything they need is on site ready. Bolts to fix the stairs to the wall, door lining, timber, plasterboard screws and nails for the cupboard if you're having one. If they have to fit any of the treads or risers use loads of glue!

When staircase is installed, cover it up. Especially if it's being stained or varnished and not painted but either way it wants protecting before the plasterer gets there and from other trade traffic with tools etc.

You can buy black protective plastic that's good (i get it from a company called SIG they might have a store near you) otherwise hardboard for the treads and risers cover the posts with something else.

If the stairs are Oak you cannot get plaster on them it'll stain you have to cover every inch!

Good luck any more questions come back to me,


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