Do I need a lintel?

[Roger Harris]

Hi all,

I'm planning on putting a side door and window in my 1950s-built detached garage. It's single thickness brick walls with a cast concrete roof.

I'm wondering about pre-stressed concrete lintels.

Given the small size of the garage (cars must have been very small then - I could get my car into the garage, but I would be stuck in the car!), the door frame and window frame would come within about 120mm of the top of the wall, which would leave no bricks between any lintel and the frame.

If the roof is cast concrete, do I need a lintel at all, or could I just take out all the bricks and put a 2x4 in there, simply to fill the gap? It occurs to me that if the roof is reinforced concrete, it's sort-of a lintel in the first place?

If I do need a lintel, would I need acrows to support the concrete roof while knocking out the bricks or is a concrete roof strong enough to hold it up while that's being done?

Lintels would be 1200mm for the door and 1500mm for the window.

Thanks in advance for your help.

Roger Harris.

 

[Doggit]

A precast concrete lintel would never rot, so is better than a piece of 2x4, and as you have a cast concrete roof, make it a much better choice. And considering the wight of the roof, a pair of acrows would be a very sensible option; better safe than sorry for the price of hiring them for a day.