Precast or Prestressed lintels

[s85]

Im having my property refurbished and as part of the works i'm upgrading all the windows. The windows currently have old wooden lintels (on the internal leaf of the 9inch wall) and I want to use this opportunity to replace all the wooden lintels with concrete lintels. Should I be using Precast lintels or Prestressed lintels? The window openings are 90cm wide. The outside leaf of the 9 inch wall has the original brick arch as the lintel.

Thanks .

 

[jks7492]

Prestressed lintels are precast lintels - the prestressed just refers to the reinforcement within the lintel.

 

[s85]

Maybe the correct question I should be asking is, should I use prestressed lintels or non prestressed lintels.

Theres something I across about one type of lintel is only effective when you build at least 3 courses of brick work over it after its been laid. I wont be able to build anything on top of the lintel in my case as im simply removing and replacing the existing lintel.

 

[^woody^]

Don't worry about the difference, just use the standard concrete lintels stocked in the merchants.

 

[George_engineer]

Maybe the correct question I should be asking is, should I use prestressed lintels or non prestressed lintels.

Theres something I across about one type of lintel is only effective when you build at least 3 courses of brick work over it after its been laid. I wont be able to build anything on top of the lintel in my case as im simply removing and replacing the existing lintel.

Don't worry about that. The fact the bricks are there is what is important as they arch over the opening reducing the load on the lintel. When they were built is not important (although do repoint and bed in the gap between the exg brick and new lintel as best as possible).

Unless you've got point loads like a purlin or steel beam bearing onto the wall immediately above (within the load triangle above the lintel) then just use the normal lintel as woody says.

 

[stuart45]

Maybe the correct question I should be asking is, should I use prestressed lintels or non prestressed lintels.

Theres something I across about one type of lintel is only effective when you build at least 3 courses of brick work over it after its been laid. I wont be able to build anything on top of the lintel in my case as im simply removing and replacing the existing lintel.

A composite lintel requires 3 courses of brickwork before a point load, which is why the rough edge should be on top to bond I the brickwork better.
Non composite can take a point load.

 

[s85]

Ok thanks.

I think I will use the 65mm x 100mm Prestressed concrete Lintel Textured 1200/1500mm available from BD.

Is there a particular way they need to be installed, ie is there a top side and bottom side? as I read somewhere that they are ever so slightly curved due to the prestressing process.

​

 

[stuart45]

The rough side is the top, but the curve should be at the top of you can see one.