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Lintel Confusion??


Joe87

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HI,

 Im in the planning stage of building a garden room and i have a few questions i hope someone can help me with. We've decided to have bi fold doors of about 4 meters long. Next to this will be a window going from the side of the bi-fold along to the corner of the building attached to another window on the right side wall. Basically the front and right side will be all door and windows.

The building will be block built, single leaf with a flat roof. Obviously the roof will be supported by the block work around all but the front and front right of the building where the door and windows will be.

 

However, Im confused what i need to have over the bi-fold doors and the corner windows to not just attach the roof joists to, but also the top of the bi-fold door and attach the windows themselves to. I've been told by a builder that a wood lintel (c24 timber etc bolted together to make the width needed) would be fine and that the bi-folds, roof joists etc can be attached to that?

 

That brings up more questions for me though. If i use a wood lintel it would have to span the 4 meters of bi fold door, the window directly to the side of it and then around the corner for the other window. So maybe about 6 meters on the front and 3.5 meters on the side. So am i able to bolt the wood lintel together to make something long enough to span the 6 meters (bi-fold and front window, unless i can get timber 6 meters long) and for the corner would the wood lintel then sit on a square corner post or something else that would take the load like a bay pole maybe?? and then another 4 meters or so of wood lintel coming of the square corner post or something else, for the side window?

 

Ive looked at single leaf lintels but i can only ever see ones that are 2.5 meters so not long enough for what i need.

 

Im really sorry if this doesnt make sense, i  know what im trying to ask but its difficult to put into words haha. Basically as simple as possible, what exists in the world that i can use to attach a bi-fold door, corner window and the roof joists above so it all stays together and doesnt collapse on me ?. I hope it makes enough sense that someone can help.

 

Thanks all for any help. Much appreciated

 

Joe

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I would just use a steel beam and post arrangement. 6m Steel would only be taking the roof loading so pretty easy to calculate the depth, same on the side return and join them on a corner post bolted to the foundations.

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What you need to consider is if the lintel drops Even a few mil your doors won’t open 

 

I used a 5 mtr steel with a hit and miss plate welded to take the outside skin

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4 hours ago, PeterW said:

I would just use a steel beam and post arrangement. 6m Steel would only be taking the roof loading so pretty easy to calculate the depth, same on the side return and join them on a corner post bolted to the foundations.

 

Thanks Peter for the reply. This sounds like an easy option. Maybe a dumb question but would I attach the roof joists to the steel beam or would I need to put a course of bricks along first? Also is it possible to attach the windows to the corner post do you know? No problem if you're unsure you have given me something to work with. Thanks. 

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4 minutes ago, Joe87 said:

 

Thanks Peter for the reply. This sounds like an easy option. Maybe a dumb question but would I attach the roof joists to the steel beam or would I need to put a course of bricks along first? Also is it possible to attach the windows to the corner post do you know? No problem if you're unsure you have given me something to work with. Thanks. 

 

Joists can go onto the beam, or just a wall plate either bolted or shot pinned to the top flange of the beam. You can use an RHS section to hold the corner up, and install it in such a way that it doesn't cause a cold bridge which will be your risk if you connect the windows directly to the post. Insulation needs to be properly designed.

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Do you have a purpose in mind for this building?

that is a big cost in glazing to put in a garden room for a few months use per year. 

 

The reason i say few few months is you mention single skin block, this makes me think it’s just for high summer, as the rest of the year it will be to cold to be in there. 

 

If you want this to work I think you need to outline the buildings purpose, then design it from there. 

 

 

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8 minutes ago, Russell griffiths said:

Do you have a purpose in mind for this building?

that is a big cost in glazing to put in a garden room for a few months use per year. 

 

The reason i say few few months is you mention single skin block, this makes me think it’s just for high summer, as the rest of the year it will be to cold to be in there. 

 

If you want this to work I think you need to outline the buildings purpose, then design it from there. 

 

 

Originally it wasn't going to be this big but the concrete pad that it will sit on is a large area so I decided to fill it rather then let it going to waste. I was planning to timber frame the inside walls, add some insulation plaster board etc. Aswell as insulate the floor and have a warm roof. It will be a games room/ bar area but also a place to store garden furniture during the winter. Currently we hang out in the garage to play pool etc, which is also a single skin with no insulation at all. I haven't looked at the windows yet but the bi fold I can get for about £2500. This is not an all in one build. This is very much going to be a thing done over time but I really wanted to get my head round everything. The walls, floor, warm roof are all straight forward but I had no real idea of how the joists would attach above the bi-fold and corner window. I have been told by a window fitter that a 90* square corner post can be used which the will have the corner windows attach to and they can be load bearing. Thanks. 

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19 minutes ago, Joe87 said:

I have been told by a window fitter that a 90* square corner post can be used which the will have the corner windows attach to and they can be load bearing.


In a conservatory, yes, with what you are designing, no. Corner posts are designed for light loads, you’re taking about taking the full load of a 4m lintel and all the roof loads into a single point. That’s not something you can do with a length of ally tube. 
 

Unless there is a compelling reason to have a frameless corner, I would bring both windows back slightly and use a 126x126 UC and box round it to make a feature and then you will have a simple and stable structure. 

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2 hours ago, PeterW said:


In a conservatory, yes, with what you are designing, no. Corner posts are designed for light loads, you’re taking about taking the full load of a 4m lintel and all the roof loads into a single point. That’s not something you can do with a length of ally tube. 
 

Unless there is a compelling reason to have a frameless corner, I would bring both windows back slightly and use a 126x126 UC and box round it to make a feature and then you will have a simple and stable structure. 

I'm glad you've said this Peter because this did worry me aswell. I was just asking him in passing when he was here to fit some windows in our house. I did wonder if the corner post would even be wide enough to support a lintel let alone take the weight. I think I will definitely change the design to pull back both the windows. It'll make life easier for us aswell I think. Thanks 

Edited by Joe87
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