# Maximum length for Concrete lintels.



## hayabusa (19 Jul 2007)

Folks, 

I have the following query. 
I have the following openings for patio doors. 

1.   2.7 Metres
2.   2.4 Metres
3.   3.6 Metres. 

In the case of no 1.  (2.7 M wide span) it has the inner leaf of blocks on the flat therefore this lintel will be 225mm wide. In the case of the outer leaf it will be a 100mm wide lintel. All that is over this is approx 5 courses of block and then the roof. Will a prestressed concrete lintel do this job. 

No 2 is a patio door on a gable. Again a 225mm wall inside then a 225 wide prestressed lintel then hollow core flooring. outside leaf is 100mm wall  with a 100mm prestressed concrete lintel. above this is approx 5 courses of block then roof. Will a prestressed concrete lintel do this job??

No 3. As per no 1, just a wider opening. Will a prestressed lintel do this job. 

My engineer has put in catnic lintels in these places, however they are over 2500 euro. Just wondering is there a cheaper method of doing this. 

I already made numerous changes to drawings so I dont want to be annoying my Engineer yet again on this one. 

Any input would be appreciated. 

Thanks.


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## ludermor (19 Jul 2007)

your engineer is the man to be asking this question


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## sydthebeat (19 Jul 2007)

many engineers accept a limit of 1.8 m for concrete lintel...

however if you can get the lintel manufacturers to stand over those spans (in writing), then your engineer will be happy....


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## Carpenter (19 Jul 2007)

In some circumstances you can achieve up to 3m spans with pc lintols, depending on the number of blockwork courses over providing the "composite action", but I'd say you're pushing it with options 1 and 3, whilst lintol no. 2 should be very "do-able" using a pc lintol as opposed to a catnic steel lintol.  Most builders are happier to use a steel lintol in anything over 2.4- 2.7m span as the risk of cracking afterwards just isn't worth it.  Your lintols sound a little expensive, who's the supplier?


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## galwaytt (20 Jul 2007)

you could shutter and pour beams cheaper than that........... IPE or RSJ beams would be a fraction of the price too..............


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## hayabusa (20 Jul 2007)

Firstly, 

Ludermor,
Did you read my mail, If so please read it again. 
I was looking for input on this by someone who has been here in the past. 
You input is of no use to me, I already know this, Please refrain from  posting useless, condesending information. 

To galwaytt, Carpenter and sydthebeat thank you for your useful input. 

Carpenter, 

I got a quote for steel lintels from Steelite in Kildare, It consisted of the following:

1.  A 2.8 M steelite lintel with insulation in the middle
2. 2 x 3.1 M  lintel,
3. a 4M Lintel
4. A 4.5 x 4.5 m lintel with 2 posts (this is a corner lintel).

All of these cost 4,700 Euro inc Vat. 

I was going to use RSJ's as per galwaytt, however i am in an exposed area ans was advised with the abount of packing (with marine ply etc etc ) that the best job would be the Catnic type lintels. 

I may consider pouring these however i will need a new spec on the rebar etc to be used. Do they use links in poured lintels or just lengths of rebar. 
All input appreciated, 

Regards


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## Sue Ellen (20 Jul 2007)

hayabusa said:


> Firstly,
> 
> Ludermor,
> Did you read my mail, If so please read it again.
> ...


 
Hayabusa,


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## ludermor (22 Jul 2007)

You are paying an engineer, use him.
A bit of manners wouldnt go astray.

And yes there would be links in the beam


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