Lintel and end bearing

[MattChan]

I need a lintel to span an opening of 1830 mm between my garage wall and the house wall. This will support the wall plate for a new pitch roof between the two.

I've had some drawings done and due to the locations of other supports in the house wall its not possible to cut into it to give the new lintel 150mm of end bearing. The drawings specify a 150mm column tied to the existing house wall which the lintel will sit on, the other end is cut into the wall over the garage. I'd like to avoid this column if possible.

I have spoken to some other people and they have said it may be possible to use a "steel" or glulam beam to span the gap without needing the support column. Is this correct? How would this beam be attached to the house wall? monty big bolts?

 

[weseeyou]

the 150mm bearing surface is to distribute the loading over a minimum area . It doesn't have to be in line with the lintol.

If you only have say a half brick thick wall or max insertion of 100mm for a bearing surface then get another short piece of steel plate 5mm thick and 200mm long by 100mm wide and place it along the bearing surface at right angles to your lintol. Then place your lintol on that.
That way the lintel will distribute the loading evenly over the required surface area of the bearing surface ie wall

 

[Shytalkz]

100 bearing onto the existing brickwork outer leaf will in all probability be more than sufficient, without the need for either a spreader plate, or padstone, for the situation you describe.

150 bearing is a standard requirement of proprietary lintel manufacturers, due principally to the way the numbers are crunched for their safe working load tables (more often than not by some civils department in a university), but the lack of 50mm's worth of bearing is not likely to cause a failure either of the lintel or the bearing, except where the loads are *very* high - not usually a problem in most domestic situations.

Bin the column, that was a stupid bit of "design" by whoever did your plans. If you can't cut into the existing wall due to obstructions, use a steel beam with an end plate and 4 bolts either chemfix or expanding, into the masonry.

 

[MattChan]

If you can't cut into the existing wall due to obstructions, use a steel beam with an end plate and 4 bolts either chemfix or expanding, into the masonry.

Superb! Thanks for that. There are obstructions so this sounds like the solution. Building control are involved obviously so would the be likely to require structural calcs for this beam?

 

[weseeyou]

no calcs should be necessary. Providing the steel plate is 100mm wide by 200mm long and at least 5mm thick .
The plate doesn't support any loading other than striaght compression. It transfers the lintol loading straight into the wall structure. You will naturally need to level the plate and bed it in mortar and make sure that your lintol sits precisely on the plate .If you use a steel lintol then it could be welded to the plate

 

[weseeyou]

100 bearing onto the existing brickwork outer leaf will in all probability be more than sufficient, without the need for either a spreader plate, or padstone, for the situation you describe.

150 bearing is a standard requirement of proprietary lintel manufacturers, due principally to the way the numbers are crunched for their safe working load tables (more often than not by some civils department in a university), but the lack of 50mm's worth of bearing is not likely to cause a failure either of the lintel or the bearing, except where the loads are *very* high - not usually a problem in most domestic situations.

sorry but as an Architect I must take issue with this . Check with your building control department or your local Architect or Civil Engineer
Manufacturers recommendations don't come into it . You must comply with the building statutes they are there for a reason . If the wall or beam moves 25mm you would only have 75mm of bearing left on maybe an old sandstone wall or pillar.Building regulations are there for a reason

 

[Eng33]

100 bearing onto the existing brickwork outer leaf will in all probability be more than sufficient, without the need for either a spreader plate, or padstone, for the situation you describe.

150 bearing is a standard requirement of proprietary lintel manufacturers, due principally to the way the numbers are crunched for their safe working load tables (more often than not by some civils department in a university), but the lack of 50mm's worth of bearing is not likely to cause a failure either of the lintel or the bearing, except where the loads are *very* high - not usually a problem in most domestic situations.

sorry but as an Architect I must take issue with this . Check with your building control department or your local Architect or Civil Engineer
Manufacturers recommendations don't come into it . You must comply with the building statutes they are there for a reason . If the wall or beam moves 25mm you would only have 75mm of bearing left on maybe an old sandstone wall or pillar.Building regulations are there for a reason

Seeing as Shytalkz is a Structural Engineer, I think he probably knows a little more about structural issues than your average building inspector...

 

[^woody^]

Should be fun

 

[Shytalkz]

sorry but as an Architect I must take issue with this . Check with your building control department or your local Architect or Civil Engineer

As an architect, then you should know the difference between a civil and a structural engineer.

You must comply with the building statutes they are there for a reason

Yes, for the guidance of wise men and the obedience of fools. BRegs is but one way of compliance: Part A can be met with by other means than slavishly following the requirements therein - even something as simple as a straightforward engineer's opinion, regardless of whether or not a paper calculation "proves" it.

If the wall or beam moves 25mm you would only have 75mm of bearing left on maybe an old sandstone wall or pillar.Building regulations are there for a reason

Ifs and ands and pots and pans: did the OP mention that he was bearing onto an old rickety wall, that was moving? And, if that was the case, hand-in-hand with using that wall would surely be some means of reintroducing stability? Would a bearing or lintel fail by dint of having "only" 75mm bearing? No, not necessarily.

 

[Shytalkz]

no calcs should be necessary. Providing the steel plate is 100mm wide by 200mm long and at least 5mm thick .

Plate length would depend entirely on the lintel reaction and the compressive strength of the wall.

The plate doesn't support any loading other than striaght compression.

It doesn't if the plate is wider than the lintel, it goes into bending. And, if it's the same width as the lintel, that would be direct compression, but then there's not much point to having it...

If you use a steel lintol then it could be welded to the plate

Why would you bother doing that?

 

[weseeyou]

Seeing as Shytalkz is a Structural Engineer, I think he probably knows a little more about structural issues than your average building inspector...

I quite agree but at the end of the day the op will still need to comply with building control whatever his views.

I am also a Chartered construction Engineer and I get fed up with spending half my time identifying and correcting building failures because builders do not follow simple rules regs and guidelines or use the correct materials .Either because they do not understand how materials perform or understand the nature of loadings.

We have no idea what loads are to be applied to this beam and bearing whether applied static ,dynamic ,snow ,etc .Just changing tiles from profile to plain can almost triple roof loadings .

If buildings fail we professionals can be personally liable for a very long time for latent defects.best be safe than sorry

 

[Shytalkz]

Superb! Thanks for that. There are obstructions so this sounds like the solution. Building control are involved obviously so would the be likely to require structural calcs for this beam?

What's the span of the roof going onto this beam? Is it just roof with storage, or are you using the loft space for accommodation?

They probably will want a calc, they like paper with lots of numbers on them, but I'd be surprised if an 8mm plate on a 178x102UB19 and 4M10 bolts wouldn't be total overkill. Have you got a brickwork detail from lintel level to eaves - if so, 8mm plate on the bottom of the UB with stiffener plates at nom 450 centres will give the requisite support to this.

Welding an end plate on a proprietary lintel is possible, but it will all work out more expensive that having a beam made up.

 

[Shytalkz]

I quite agree but at the end of the day the op will still need to comply with building control whatever his views.

Quite true, but armed with some pragmatic advice, he can at least argue the toss with them if they (as happens) go totally overboard with their requirements for Part A issues.

I am also a Chartered construction Engineer...

Forgive me, but there's a world of difference twixt that qualification and that of a chartered structural engineer.

... and I get fed up with spending half my time identifying and correcting building failures because builders do not follow simple rules regs and guidelines or use the correct materials .Either because they do not understand how materials perform or understand the nature of loadings.

Yes, but are those faults necessarily a problem, or merely non-compliance with some set of rules that do not always have any basis in reality?

We have no idea what loads are to be applied to this beam and bearing whether applied static ,dynamic ,snow ,etc .Just changing tiles from profile to plain can almost triple roof loadings

Oh come on, it's spanning 1800 holding up a roof. Dynamic loads in that situation? Snow will be part of the live loading composition for the roof load. Design for concrete tiles dead load (unless it's obviously something like shingles) and there's no worry about adequacy of applied loading.

If buildings fail we professionals can be personally liable for a very long time for latent defects.best be safe than sorry

Do you mean overdesign something to make 200% sure it's never likely to fail? That's not proper engineering design: that's defensive litigation-conscious design, which really gets my goat. Just because it doesn't work on a piece of paper does not mean it won't in reality and with the plethora of software-led design packages that are available today, engineering judgment often goes out of the window, leading to grossly over-designed structures and more unnecessary expense for the client.

 

[weseeyou]

I appreciate your sentiments about overkill but frankly I am always forced to take a less antaganistic view and try get BC inspectors on my side if I can.As Architect and overall project manager I need to keep the clients best interests in mind at all times

If BC inspectors want to be difficult they can make you jump through hoops, as can the Planners if they choose to.

Whilst I have an overview of all aspects of the construction process including structural elements and can do straightforward structural calcs etc if I need to,
I would always advocate the Client appoint a Structural Engineer such as yourself.

The solution that I outlined for the OP,that you kindly detailed, would be a cheap, simple solution , guaranteed to be acceptable to BC

 

[noseall]

If BC inspectors want to be difficult they can make you jump through hoops, as can the Planners if they choose to.

if you play within the rules, then they can not do any such thing.