Jump to content

Increasing Existing Wall Opening


Recommended Posts

Hi,
I'm looking to create a staircase landing to a new upper floor I am creating. As part of it I wish to use an existing doorway opening, and double the width of it to create a landing for the new staircase.  From what I have read this would require increasing the bearing length of most lintels from 100mm to 150mm.
As the new floor will be approx 400/500mm lower than the existing height, what recommendations are there for lintels to ideally keep bearing to a minimum as one side enters a party wall shown in light pink on image attached, and keeping the existing lintel in place to remove some of the load on the new lintel to be installed ?

 

Edit ~ the wall is masonry 140mm

Hopefully this makes sense, many thanks in advance

 

Graham

landingdoorway.jpg

Edited by gs412m
Link to comment
Share on other sites

The existing lintel will not reduce the load on the new lintel it potentially will actually increase the load. 

 

The dead load and any imposed loads (if it supports any floor joists etc.) of the masonry above the existing lintel is being supported at two points in the existing wall this then creates a greater point load at the bearing surfaces, if you then transfer this down onto the new lintel you are actually going to create a higher point load right in the centre - weakest point - than if you just bricked up to the old lintel.

 

What I would do is support the wall at about 3 points (depending on width of opening) 1 about 2 courses above the new lintel position and directly under the LHS of the old lintel, then another further left and above the proposed new lintel the third would be under the old lintel too just to take the weight of the wall above well.

 

Then remove the wall to create your opening, and fit the new lintel, then build brick up under the old lintel well, with a good mortar bed pushed in hard so the old lintel effectively just becomes a long brick and is fully supported. The old lintels load becomes fully supported full length.

 

 

  • Like 1
Link to comment
Share on other sites

11 minutes ago, Declan52 said:

What's above the wall?? 

Is it supporting another floor or the roof??

 

It's the rear wall of the house upstairs so possibly the roof to an extent, as there are two verge large timber beams  in the loft ?

Link to comment
Share on other sites

43 minutes ago, gs412m said:

The opening is going to be greater than 1200mm, so I will have to have 150mm bearing minimum ? No other method / lintel type to reduce this depth into the party wall ?

 

 

The lintel is not the issue, it is the bearing surface, you could use a solid piece of titanium but the fact is you are still trying to support a >1200mm span on a 100mm piece of the existing wall. Even with a concrete pad-stone it is not a large bearing surface. One option may be for you to move the whole opening left a bit and have a stub of wall (properly cut into the existing wall) built to give you the required bearing surface without needing to eat into the party wall, another option would be a vertical steel. Of course these two only work if there is a supporting wall lower down that you can build on. These are a bit excessive for your needs but give you an idea. 

steels.jpg.52e4edc76a54973c38b73793176aa303.jpg

 

If you take a hammer and hit the edge of concrete what happens? Move it in about 50mm and try again - same principle. 

 

Edited by Carrerahill
  • Like 1
Link to comment
Share on other sites

20 hours ago, gs412m said:

~ the wall is masonry 140mm

Is this the party wall? If so then I would have thought you have plenty of bearing on a good padstone.

Link to comment
Share on other sites

No....the internal wall that the lintel is in currently is 140mm deep. Have had a quick google search and it looks like lintel installation is covered under the Party Wall Act, so all I require is to inform the neighbour with two months notice.
Just popped out the door and measured it, if the party wall is this deep through the building it is approx 330mm thick, so 150mm will not even go halfway through
image.png.e94866e2f325c04fac0637bebf1d81d7.png

Link to comment
Share on other sites

27 minutes ago, gs412m said:

Just popped out the door and measured it, if the party wall is this deep through the building it is approx 330mm thick, so 150mm will not even go halfway through

 

Did you check to make sure it dos not step in a bit inside behind the door?

Link to comment
Share on other sites

I’d be amazed if your party wall was 330mm deep,;one brick (9 inches) was standard in solid wall construction & the Victorian Builders wouldn’t have over engineered out of the goodness of their hearts. When you say the bearing wall is 140mm are you measuring plaster face to plaster face?

Link to comment
Share on other sites

  • 2 weeks later...

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
×
×
  • Create New...