Stair riser - structural?

[dormermike]

Hi folks

I'm laying a 18mm engineered floor and have got to the stairs and unsure how to do the detail around the bottom step.

Ideally I'd like to undercut the bottom riser and slide the floor underneath. I assume the post next to the riser / bottom step is likely to be structural but what about the riser itself?

The staircase is open underneath so I really don't want to weaken it. See photo.

Any help appreciated!!
Thanks
Mike

 

[Doggit]

Take the carpet off the riser first, and have a more detailed look at it, but I wouldn't be inclined to touch it as the stairs are often resting on the ground. It should be safe to cut back some of the wall string, but might be worth putting in a couple of bolts in the string underneath the stairs to play safe. Oddly enough, the post isn't that structural, as it's holding up the handrail, but it'll be fixed to the outer string, and fixed into the floor.

 

[dormermike]

Ah good idea!! Doh why I didn't think of that I'm not sure. Carpet off and the riser just looks like thin ply bent around.. it's not sat on the floor as there is a gap and it gives when pressed.

I guess I have my answer.. should be safe to cut?

Thanks! !

 

[Doggit]

It's going to be providing a degree of support for the tread, so if you cut too much off of it, the tread will drop and creak when you step on it. Engineered wood doesn't expand and contract as much as real wood does, but you've got to allow for it. You'll need to obviously cust a little higher to get the wood underneath, and then possibly glue or fix a piece of wood behind the ply after the the floors in. Use spacers to support the tread in the meantime.

 

[bobsuerita]

the only way to deal with the bullnose correctly is cut around it and leave a 10mm gap then put some cork in there the carpet will then hide same with the string but you will see the cork so neatly does it the newel post you can put the flooring to it mark then cut into it about half inch enough to put flooring under and allow for some expansion as from summer to winter you will get
just dont cut the newel completly or or the bullnose you will end up with no end of problems cant count how many times ive had to repair stairs from muppets doing this

 

[dormermike]

Sorry what is the bull nose? Isn't that the bit you step on?

Or the bendy facia bit I've been calling a riser..

Not planning on cutting the stringer or the post, just the plywood and only 23mm or so. Push comes shove I can get behind that bottom step as it's just some plasterboard covering the back of it.

Definitely don't want to do anything that will make it creak!

 

[big-all]

will it have carpet on the finished riser ??
is the bottom step at all loose ??

 

[dormermike]

Probably won't put carpet back. Thinking of cleaning up the ply and oiling it.

Bottom step is rock solid

 

[big-all]

my solution if it where possible would be remove the step add timber to the back edge off the strait edge and and trim the full thickness off the strait and the side
or
assuming the riser is formed off timber that is greater than 12mm just undercut by say 8mm just aim to leave full support on the curved edge to stop the step floating

 

[John D v2.0]

The newel and the strings are the structural parts, but the riser is providing a connection to the steps above to stop them bending and give rigidity reduce deflection at the nose. You can always glue another one behind with Pu glue and screws, then loosen the front one from the floor. But stairs generally shouldn't be messed with too much as most parts are there for a reason.

 

[Tigercubrider]

Would it be possible to fit a couple/more vertical bits of timber from the rear?
I.e. A couple of 6" 2x2 wedged between the floor and front of the step, supporting the tread?

 

[dormermike]

OK thanks everyone.

Sounds like I'm OK to undercut 23mm of the ply but beefing up the back of it with extra support wouldn't go amiss. I'm going to scotia bead around the newel rather than cut into that post. Same with the string.

 

[dormermike]

Started cutting and noticed about 1mm flex when stood on the step. Lost my bottle and decided I'll live with a Scotia than run the flooring underneath!!

 

[Doggit]

Don't bottle out yet, jut take it carefully, and you should be able to leave there after the floors been pushed under. You may need to notch the floor around the cable, but as long as you're careful, then you should be fine. See if you can find out where the cable goes, and see if it's redundant/not needed.

 

[big-all]

i though he meant deflection ??