Narrowing landing

[robmorgan]

Hi all,

I'm planning to fit a new banister. While I'm there, I'd like to make some changes to the landing (left of photo).

Untitled

• robmorgan
• 26 Nov 2012
• 1

For some reason it's about 6cm wider at the far end, so I'd like to straighten it up. I'd also like to narrow it by one board width to accommodate the handrail fittings I have in mind and make the opening a bit wider.

Having taken up the boards shown in the photo it seems the landing joists have no support at the right ends. They simply sit on and protrude from the load bearing wall on the left with the right ends hanging in mid air. Is this quite typical?

If so, am I missing something or would it be OK to shorten the joists by cutting them along the red line shown in the photo?

Thanks,

Rob

 

[big-all]

would involve major structural alterations and possibly a bit off steelwork

 

[rjm2k]

I'm no structural engineer but it looks like the joists are resting on 2 walls to the left so the small area you are talking about is an overhang from the wall you mention. Presumably there is enough weight on the other side (including the wall sitting on the joists) to allow this small area to stay up effectively unsupported. Cutting the joists like you mention will reduce the unsupported area so at a guess would be ok, however as I say, I'm not a structural engineer so if I were you I'd get someone to look at it. Is there anything nailed onto the ends of these joists? Again, no qualifications but attaching a timber running along the ends would presumably join them up and help to distribute any load on one of them to the rest. Still unsupported though.

edit - just noticed, great name btw

 

[robmorgan]

would involve major structural alterations and possibly a bit off steelwork

If definitely so then I won't bother!

But there's literally nothing supporting these joists other than the load bearing wall on the left. They then continue a further 3m under the main bedroom before meeting the external wall.

They're already hanging in mid air air so I can't see how taking 10 - 15cm off the ends of them will affect the structural integrity?

 

[tony1851]

The joists are obviously cantilevered over the wall, so cutting the ends shorter will not pose a structural problem.

 

[robmorgan]

I'm no structural engineer but it looks like the joists are resting on 2 walls to the left so the small area you are talking about is an overhang from the wall you mention. Presumably there is enough weight on the other side (including the wall sitting on the joists) to allow this small area to stay up effectively unsupported. Cutting the joists like you mention will reduce the unsupported area so at a guess would be ok, however as I say, I'm not a structural engineer so if I were you I'd get someone to look at it. Is there anything nailed onto the ends of these joists? Again, no qualifications but attaching a timber running along the ends would presumably join them up and help to distribute any load on one of them to the rest. Still unsupported though.

Yep, resting on 2 wall to the left, the load bearing one shown and then the external wall some 3m distant.

There's just a 10mm thick plank nailed to the ends of the joists, painted white and purely cosmetic I would think. Can't imagine it's adding any real support and in any case I'd reinstate it once I've shortened the joists.

 

[robmorgan]

The joists are obviously cantilevered over the wall, so cutting the ends shorter will not pose a structural problem.

"Cantilevered" is the word I was looking for - thanks!

Pretty standard practice then?

 

[tony1851]

The joists are obviously cantilevered over the wall, so cutting the ends shorter will not pose a structural problem.

"Cantilevered" is the word I was looking for - thanks!

Pretty standard practice then?

Yes - just get on with it!

 

[theoldun]

Without wishing to be involved in an argument Tony and always willing to learn, if the landing joists are cantilevered with out being fixed to a trimmer, then this is the very first time that we have seen this practice.
The standard practice on any stairwell trimming is, baulk head trimmer, landing trimmer and run trimmer.
On previous photo posted 19th Nov, before you pulled down the baulk head wall, it clearly shows a baulk head trimmer. There mist be a landing trimmer in place for stairs to pitch on to, so why is there no run trimmer.
QUOTE There's just a 10mm thick plank nailed to the ends of the joists, painted white and purely cosmetic I would think.
We note your comment, I would think.
This so called 10mm plank is your apron lining and would have continued round your balk head.
Would suggest, that you remove apron lining to determine whether there is a trimmer behind all in accordance with standard stairwell openings.
Would be very interest to know.
Regards oldun

 

[robmorgan]

Thanks oldun - I'm here to learn and you seem to know what you're talking about

Googled the terms you mentioned and came across this:

There is still a trimming joist beneath where the baulk head wall used to be - I didn't remove this. It spans the entire landing and stairwell and disappears into the load bearing walls either side, so presumably it spans the entire building.

However, there definitely isn't a trimmer joist running along the edge of the landing, just the apron lining nailed onto the ends of the cantilevered joists.

I must admit I thought this was odd when I saw it, and my first thought was it might make sense to add what I now know to be called a landing trimmer, just for good measure.

That said it's been standing for 75 odd years so I don't suppose it's about to come down!

So, oldun - in your opinion:

1. Can I safely cut the joists as originally proposed? This would make for a 950mm wide landing and a 1100mm wide opening. Any regs I need to be aware of here?

2. If so, should I add a landing trimmer?

 

[rjm2k]

In the pic above, the joists are only going as far as the load bearing wall and appear much thinner than the trimmers.

Presumably in the case of the OP, the joists are running the full length of the building rather than to just one wall so are fully cantilevered and with the additional rigidity provided by the apron trimmer plus the floorboard nailed to the top, there is enough support for it to be safe?

 

[theoldun]

Always prepared to help any one prepared to help their selves.
Your drawing now shows you the correct way a stair well should be trimmed and the reason for our doubts in our previous post.
Not prepared to give you our opinion, but will tell you what we would do if it was our house.
Couple points first.
Very much doubt if two main trimmers go across bedroom floor as they would need to be 5400 in length. Would assume they are sitting on partition wall below. With that in mind are you certain that landing trimmers go across bed room and are definitely cantilevered over partition below?
Any how that is by the way. Throw a baulk across underside of landing joists and ground floor if suspended with three acrows in between. Strike line across landing joists where you wish to cut. Throw a 63mm by depth of joist in as stair run trimmer and hang the lot on timber to timber hangers. It is a bit fiddly but easy enough. You will need new apron lining and cover fillet to hide cut to ground floor ceiling line. You will need new horizontal 90 degree or newel handrail for existing newel, or mitre one up yourself. New newel and turning for far end and half newel for baulk head.
May stand for another 75 years as it is, but then again the Titanic was not supposed to sink., Your choice.
Come back for anything you are not sure of.
Regards oldun

 

[chickenlips]

The apron is for asthetic purposes only.
Usually on cantilever joists, there is a closing joist running perpendicular to the joists (like a header joist or landing trimmer) but does not take support off the 2 trimmers. Commonly refered to as a cantilvere closure, which is what has been done here IMO.

The question you asked originally, would be fine to do. You could add a larger section to close off the joists ( acting as a landing trimmer) but wouldnt see the need to go OTT, 25mm or 38 would be more than suffice. Nailed or screwed to the ends. Still allowing for a thin apron to be added if needed. Usually 6/9mm ply/mdf etc is used for aprons (when painting)