Lintels for cavity that is 1-2" wide

[helicopterred]

I am considering raising my kitchen/outhouse roof as it is too low.

The ceiling height is just over 2 metres, it is original but i think it used to be a toilet and something else, coal shed perhaps as that is what my neighbours looks like, my neighbours is divided in two lengthways, where mine is one room and part of the kitchen.

The house was built in 1938 has a cavity which is probably only just about an inch and a half possibly a bit more wide!

It currently has a lintel which looks too narrow but i guess it is fine? as it looks old and there have been no issues!

I would like to raise this up, im looking at replacing with a 195mm wide I Beam ITG lintel or something similar? due to the cavity width, which seems to limit my choice to solid wall lintels or should i do two separate lintels for each leaf, this is on an external normal two floors semi detached house so is a load bearing wall

I also want to remove a return on one side as it is on the long back wall and not at a corner so the lintel would need to be bigger hence having to purchase a new one

My main concern is to achieve the minimum 150mm bearing surface on the side wall (it currently is just under 150mm) i would have to corbel slightly into the cavity and im not sure if i can do this within building control, it is not a well controlled cavity as there are lots of it that are filled with rubble that is trapped as i found when renovating my bathroom and a few windows!

I want to sort all the facts out before i go to building control as i may leave it where it is as there are to many potential issues, but just raise the roof anyway by approx three brick courses

Any help would be appreciated

 

[noseall]

There are 50mm cavity lintels available in all sizes and duty (strengths) .

 

[helicopterred]

Hi Thanks for your reply i dont think i could get a 50mm cavity lintel in due to the gap being around about that or slightly less and also due to all the excess mortar that has not been removed when built!
Thanks

 

[^woody^]

Use two L shape lintels. Or solid one internally and the L lintel externally. Don't forget cavity tray.

 

[helicopterred]

Thankyou for that is there any suggestions regarding corbeling into the cavity to accommodate the 150mm bearing surface for the lintel

Cheers

 

[noseall]

Thankyou for that is there any suggestions regarding corbeling into the cavity to accommodate the 150mm bearing surface for the lintel

Cheers

Eh? The 150mm bearing is in regards to bearing length not width or am I missing something.

 

[helicopterred]

Hi yes im referring to the side wall so the lintel/RSJ would pass across the Brick, or the inner leaf of a external cavity wall so not sufficient bearing surface unless i can install a pad into the cavity if that makes sense.

 

[^woody^]

Lintels can have 100mm bearings under normal loading and do not need 150mm

 

[helicopterred]

Thankyou for that, that was my only worry as it could of meant a problem going ahead now I know there is no problems going forward I will contact building control
Many thanks

 

[helicopterred]

Hi another question what is the best way to replace the RSJ?

I Will support both internal and external walls with strong boys 2.1 m span so minimum 3 but may put one at each end of wall and evenly space another 2 between or is that ott?

What's the next step? Remove old RSJ build up wall then place new uni beams in place?
Or do I need to remove RSJ the position new beams, acro them up then build underneath upto the beams?

Just wondering if there is any issue leaving on strong boys with no rsj's in place whilst building up the wall?

Cheers

 

[helicopterred]

Hi, right old rsj is now out no mishaps so far (touch wood, touch wood!!)
I have laid my engineering bricks level etc. i was going to build up with engineering bricks but went against that due to the metric and imperial difference, which leads me to my next questions

As im using metric engineering bricks the finish height of the bricks leaves a much larger gap than i anticipated

I was told by the building control officer to use the i52x89 so whats the next step do i place packing under the bricks to move it up or do i have no alternative other than buying a padstone? or can the bricks be placed on there side?
Or I have some old proper victorian slate (fire mantlepiece) so this is the decent stuff me thinks will that be ok? fine by me but i dont want to dissapoint the building control officer