Hi
Whats the difference between a precast and a prestressed concrete lintel ?
Whats the difference between a precast and a prestressed concrete lintel ?
Precast and PreStressed Concrete Lintels
- Thread starter self builder 123
- Start date
Pre-cast is a generic term - basically its made in a mould and then lifted into place - as opposed to cast in-situ
Pre-stressing is where the reinforcement is pulled tight and the lintel has a slight chamber (or arch shape) and this will take more load than a 'normal' flat lintel
Many people mix up the two terms and actually just mean a concrete lintel
Pre-stressing is where the reinforcement is pulled tight and the lintel has a slight chamber (or arch shape) and this will take more load than a 'normal' flat lintel
Many people mix up the two terms and actually just mean a concrete lintel
Precast is a concrete lintel formed with "normal" high yield or mild rebar that is placed and the concrete then cast.
Prestressed is a concrete lintel with smaller rebar comprising thin high yield steel tendons which are put into tension ie pulled apart as the concrete is cast. These are cut when the concrete has cured, which puts the concrete into compression as the wires try to shorten themselves. The reason for this is that concrete is strong in compression, weak in tension: it therefore reduces the tensile stresses in the concrete when a load is applied ie it's much stronger.
Prestressed is a concrete lintel with smaller rebar comprising thin high yield steel tendons which are put into tension ie pulled apart as the concrete is cast. These are cut when the concrete has cured, which puts the concrete into compression as the wires try to shorten themselves. The reason for this is that concrete is strong in compression, weak in tension: it therefore reduces the tensile stresses in the concrete when a load is applied ie it's much stronger.
there are also two types of builder....
.....pre-cash and pretty stressed!
.....pre-cash and pretty stressed!
LOL you can see who charges by the hour/word.
Actually that is basic C&G brickwork stuff
... who needs structural lessons, pah! 
BTW, I don't think you would want pre-stressed lintels on your house - it messes up the coursing and there should not really be much need for them in terms of load
Actually that is basic C&G brickwork stuff
... who needs structural lessons, pah! BTW, I don't think you would want pre-stressed lintels on your house - it messes up the coursing and there should not really be much need for them in terms of load
- Joined
- 8 May 2026
- Messages
- 1
- Reaction score
- 0
- Country
"The choice between precast and prestressed lintels isn't just about cost; it's about structural behavior. While a standard precast lintel is reliable for common masonry, prestressing adds an 'active' internal strength that allows for longer spans and slimmer profiles without the risk of deflection."
No. It shouldn't be banana shaped.
The internal reinforcement may be bowed within it, in which case there's a right and wrong way up which should be marked.
More often the reinforcement is just stretched lengthways, so there's internal compression acting upon the surrounding concrete. So some of the tension taken by the concrete under load only reverses this compression, returning it to a stress-free situation.
Concrete lintels are definitely not curved, pre-stressed or not!
You were responding to Woody talking about prestressed concrete elements, which do sometimes have a slight upward camber. Like B&B floor beams for example.
The rest of your post I questioned above is made up waffle.
Normal PSC lintels are straight but on a larger scale prestressed beams are often percambered to improve their performance.
The reinforcing bars in PSC lintels are straight because they are tensioned before the concrete is placed. It is not uncommon for post tensioned beams to have curved tendons though.
Usually the top of a PSC lintel is rough to better key to the mortar but the reinforcement is often BUT NOT ALWAYS symettric so putting it in upside down is not always dangeroius but a silly habit to get in to.
The reinforcing bars in PSC lintels are straight because they are tensioned before the concrete is placed. It is not uncommon for post tensioned beams to have curved tendons though.
Usually the top of a PSC lintel is rough to better key to the mortar but the reinforcement is often BUT NOT ALWAYS symettric so putting it in upside down is not always dangeroius but a silly habit to get in to.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
