Joe87

Which lintel?

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Hi all, 

I have a 4 meter opening in a garden room I've built for some bifolds but need a lintel above to stop deflection of the doors. 

 

Which lintel would be best for a single skin dense concrete block wall though? Above the door maybe a course of dense concrete blocks and then a warm flat roof over the whole thing. 

 

Building the walls was fairly straight forward but lintels seem to be a minefield. There seems to be so many types. 

 

Thanks for any help

 

Joe

Edited by Joe87

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14 minutes ago, Joe87 said:

Hi all, 

I have a 4 meter opening in a garden room I've built for some bifolds but need a lintel above to stop deflection of the doors. 

 

Which lintel would be best for a single skin dense concrete block wall though? Above the door maybe a course of dense concrete blocks and then a warm flat roof over the whole thing. 

 

Building the walls was fairly straight forward but lintels seem to be a minefield. There seems to be so many types. 

 

Thanks for any help

 

Joe

I wouldn’t use a thing other than steel 

With steel prices so low there isn’t a massive difference 

A 5 mill drop above the bigolds will cause them not to open 

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1 hour ago, nod said:

I wouldn’t use a thing other than steel 

With steel prices so low there isn’t a massive difference 

A 5 mill drop above the bigolds will cause them not to open 

 

What type of lintel would you think best? Something like an I beam or is there another type better suited do you know? 

 

Also if I did use an I beam, do I simply put a bed of mortar directly on top of the steel and then put another course of bricks to finish of the wall? 

 

Thanks for the reply. 

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How are you planning on insulating this room ..? That will have a bearing on the beam type and also the lintel construction method 

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If it is exposed it would be best galvanised.  A Universal Beam (UB) would be most common.  You will need advice from someone on the section size.

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17 minutes ago, PeterW said:

How are you planning on insulating this room ..? That will have a bearing on the beam type and also the lintel construction method 

I planned on a timber frame inside with insulation board and plastering to finish it all off. 

 

17 minutes ago, Mr Punter said:

If it is exposed it would be best galvanised.  A Universal Beam (UB) would be most common.  You will need advice from someone on the section size.

 

I was told the same thing by someone else that I could use a UB but just wanted to be sure here before I went ahead and made a mistake. The opening is about 4 meters and it won't really be holding much weight above. Just a flat roof. So nothing extreme like a second floor or anything. 

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The problem you have with lintels 

If there’s not much above them they are likely to move 

Anything over 2ntrs I used a steel with a hit and mis plate 

For one skin a steel is perfect 

Especially with bifold 

 

This is one of three that I’ve just fitted 

828E1209-C299-45A9-A609-A2068C02FF7C.jpeg

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IG do a free design service if you send them specs of your building, they'll run calculations and specify a lintel for the job, i've used it before, and it was pretty quick

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49 minutes ago, Joe87 said:

I planned on a timber frame inside with insulation board and plastering to finish it all off. 

 

 

I was told the same thing by someone else that I could use a UB but just wanted to be sure here before I went ahead and made a mistake. The opening is about 4 meters and it won't really be holding much weight above. Just a flat roof. So nothing extreme like a second floor or anything. 


OK so which way do the roof joists run ..?? If they land on the lintel then there is a huge load, if they are parallel then the load is negligible.  That affects the size of the beam. 

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16 minutes ago, PeterW said:


OK so which way do the roof joists run ..?? If they land on the lintel then there is a huge load, if they are parallel then the load is negligible.  That affects the size of the beam. 

If you ask a SE He will tell a low amount of weight isn’t good

Lintels rely on weight to keep everything in place 

We have a flat roof and a metre of double skinned block above our orangery SE still class it as low weight and not suitable for catnics etc 

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Yep hence why I said beam size as lintels to 4m length really don’t exist in single skin. I agree with @nod that you need an SE to design this as it needs to be stiff enough to both resist bending and also resist twisting over that length. 

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End bearings for steels are also important.  Normally concrete padstones but sometimes steel posts are required.

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7 hours ago, PeterW said:


OK so which way do the roof joists run ..?? If they land on the lintel then there is a huge load, if they are parallel then the load is negligible.  That affects the size of the beam. 

 

The roof joists would be running away from the lintel not across it. So if the lintel is left to right then the joists would run backwards from it. I did forget to say aswell that the opening has an end pier on each side of it. So two dense concrete blocks laying face down and then two side by side to make the end pier. So the area the lintel would rest on would be about 215mm rather then the 100mm of the block edge. I hope that makes sence, my explaining of these things is not great.

 

7 hours ago, nod said:

The problem you have with lintels 

If there’s not much above them they are likely to move 

Anything over 2ntrs I used a steel with a hit and mis plate 

For one skin a steel is perfect 

Especially with bifold 

 

This is one of three that I’ve just fitted 

828E1209-C299-45A9-A609-A2068C02FF7C.jpeg

 

How big was this opening Nod in the image? It looks good. Do you have an example of what you would use over a 4 meter span, like a website link or something? Sorry to be a pain.

 

Thanks! I appreciate the help

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Just phone or email a couple of structural engineers for a quote to size the steel and spec the bearings.  You will need drawings, including the roof makeup.  The cost is v. low.

 

They will spec something that will work without being heavier than needed, which will be far better when it comes to installing it.

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1 hour ago, Joe87 said:

 

The roof joists would be running away from the lintel not across it. So if the lintel is left to right then the joists would run backwards from it. I did forget to say aswell that the opening has an end pier on each side of it. So two dense concrete blocks laying face down and then two side by side to make the end pier. So the area the lintel would rest on would be about 215mm rather then the 100mm of the block edge. I hope that makes sence, my explaining of these things is not great.

 

 

How big was this opening Nod in the image? It looks good. Do you have an example of what you would use over a 4 meter span, like a website link or something? Sorry to be a pain.

 

Thanks! I appreciate the help

4 mtr 

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1 hour ago, Joe87 said:

 

The roof joists would be running away from the lintel not across it. So if the lintel is left to right then the joists would run backwards from it. I did forget to say aswell that the opening has an end pier on each side of it. So two dense concrete blocks laying face down and then two side by side to make the end pier. So the area the lintel would rest on would be about 215mm rather then the 100mm of the block edge. I hope that makes sence, my explaining of these things is not great.

 

 

How big was this opening Nod in the image? It looks good. Do you have an example of what you would use over a 4 meter span, like a website link or something? Sorry to be a pain.

 

Thanks! I appreciate the help

The handy thing I find with a steel 

is that you can jack the frame up tight against the underside and know it will never move 

The four that we fitted a few weeks back and the one on my house have no adjustment So you are relying on Toe and healing the glass Any movement and the doors won’t open 

 

Our structural engineer refers to lintels as his bread and butter jobs 

and hates any lintel over 2000 mil 

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10 hours ago, nod said:

The handy thing I find with a steel 

is that you can jack the frame up tight against the underside and know it will never move 

The four that we fitted a few weeks back and the one on my house have no adjustment So you are relying on Toe and healing the glass Any movement and the doors won’t open 

 

Our structural engineer refers to lintels as his bread and butter jobs 

and hates any lintel over 2000 mil 

Thanks nod. So what I'm looking for is a steel (by this do you mean a universal beam?) with a hit and miss plate. I'm glad to hear you have done so many. 

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19 minutes ago, Joe87 said:

Thanks nod. So what I'm looking for is a steel (by this do you mean a universal beam?) with a hit and miss plate. I'm glad to hear you have done so many. 

If you are single skin brick or block an Straight forward RSJ  will be fine If double Skin a welded plate is added to the underside to carry the second skin 

 

You will be suprised how little difference there is in price between a Rsj and a good quality lintel 

 

Once the beam is in you can forget about it and will give you a solid fixing points 

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