advice on lintels

[nottsrob184]

Hello.....i am looking at widening an existing opening in an outer house wall that is brick outer and block inner with a 50mm cavity.
I need to open it to 3metres wide so i can carry thru the ceiling from the house to a new extension, (single storey)
On the inner side of the house is a joist running parrellel to the opening so there is nothing above to support other than brick and block work.
Problem is i need to install a lintel but cannot support from outside and also inside the house as the existing joist is in the way of using needles.

Will strong boys do?...only issue i can think of is that they will need to be too close to the house wall that i can't fit the lintel.

Also...is there a lintel i can use (concrete or box lintel) that is 65mm x 255 that is rated to support brick and block above?.
Thanks

 

[hotrod]

Also...is there a lintel i can use (concrete or box lintel) that is 65mm x 255 that is rated to support brick and block above?.

You don't say what loadings you've got above but a 3300mm concrete lintel @ those dims ain't going to hold much so I very much doubt it. You're looking at a IG L1/S 50 or L1/HD 50:-

or Catnic equivalent thereof should see you right - but you need to confirm any heavy/unusual loadings. *You would need to go for a 3600mm in the IG as they don't manufacturer a 3300mm so you would have 300mm end bearings either side on a 3000mm span*

EDIT: Sorry, you have mentionned loadings, just seen this:-

(single storey)
On the inner side of the house is a joist running parrellel to the opening so there is nothing above to support other than brick and block work.

Must be the ale , how many courses above the opening do you need to support?

 

[nottsrob184]

the brick courses that will be above the lintel are up to the top of the house. so i guess about 10-15 in the triangle above the lintel.
I am concerned that if i use strong boys which will be close to the house wall....i will not have enough room to install a lintel of the type you showed.

Thanks for reply

 

[^woody^]

Strongboys can not be used for both leaves of a cavity wall

You need to insert Strongboys high enough so as the lintel can be inserted beneath them

 

[theoldun]

The joist is no problem. The problem may arise depending on what stage extension is.

Is extension started, finished plate high or what?

oldun

 

[chappers]

needle through above the joist ,, take out the brickwork up to the needles, fit your lintel and then brick it all back up