Fitting lintel for new windows

One lintel will do. Make sure to allow for bearing That means the width of the window plus 150mm either side . So that means the width of the window plus 300mm equals the length of the lintel you will need. Get a prestressed one. One lintel will do so long as it covers the width of the wall. Michael.

If your planning second stories A heavy duty Lintel. Finishing of 1st level, above windows/Doors. A cavity closure lintel Spans both

The answer is yes. It’s the type of lintel in terms of strength, constructed into situ appearance and thermal abilities that are the real questions.

Depending on the construction of the wall depends on what support is required ie a cavity wall requires both leaves supporting and a cavity tray inserting ,a traditional 9” wall requires support on the full 9” width of the wall normally 2 lintols or a reverse T lintol Most lintol manufacturers have a great catalogue which shows which lintol can be used over differing construction of openings and if a heavy duty or special lintols would be required eg point loads or concrete floor construction above are just a few examples

If there’s masonry above the proposed window, on BOTH walls (or skins) then you will need a lintel on both walls or a steel “catnik” lintel which spans both walls and has its own damp tray so no DPM needed. Weep vents are still required. Catnik lintels allow for bricks, stone or a dressed stone or artificial stone head to be cemented ontop of it.

If the wall is 9” thick and the exterior is a face work wall then you will require a box lintel If you have a cavity wall and the exterior is facework then you will need a catnip lintel. You will need a 150mm bearing each side I.e 1.200mm opening you would need a1.500mm lintel