Enlarging bathroom window

[cjard]

but cant see why it wont work

Any thoughts on this?

Unless I've missed something, youre proposing making 2 prestressed concrete lintels into 1 lintel by joining them together with glue, metal rods and concrete, and accepting that it will have a chunk in the middle that is not prestressed, and the 2 parts are secured to each other by a system under tension rather than compression?

Er..

 

[jackthehat2]

Assuming it's a pre stressed lintel...

It's another idea put out there- not saying that I'd be going down that route.

I doubt you can call hilti hit a glue- I can assure you that on a pull test the concrete around the rods/bars will fail before the bars pull from the resin.

Regards

Will post the reply from Hilti on here as soon as I receive a reply.

Youtube video on the "glue" tested to 16ton pull
http://www.youtube.com/watch?v=DPXXHleTSeo

 

[jackthehat2]

Received a reply from hilti today:

The intention is/was to drill 4 axial holes to a depth of 100mm into the faces of both lintels.

Hi Jack,
Hilti HIT RE500 is designed for use into a drilled hole, I suspect in this case the intention is to grind out a slot and bed the rebar in the resin at the bottom of the slot. This is a standard technique but not one that we have any experience of so I’m unable to say this would work.
If you can drill the lintels axially and then resin the rods into the resulting holes then the task becomes a standard drilled in rebar application HIT RE 500 is an appropriate resin mortar for the application.


Regards,

Richard Laybourn
Senior Support Engineer

For and on behalf of
Hilti (Gt Britain) Ltd.
1 Trafford Wharf Road | Trafford Park
Manchester M17 1BY

Hi Jack,

In principle this method is fine however I would expect the hole depth to be deeper, something like 300mm, to ensure continuity of load transfer between the concrete and the reinforcement over the full length of the lintel.
With the short embedment depth that you propose you would potentially get a brittle failure of the lintel near the connection because the load could not be transferred between the original reinforcement and the small length of concrete where the anchor is drilled in, to the new reinforcement.

I have attached the ETA for the HIT RE500 with rebar which covers this type of connection.

Regards,

Richard Laybourn
Senior Support Engineer

For and on behalf of
Hilti (Gt Britain) Ltd.
1 Trafford Wharf Road | Trafford Park
Manchester M17 1BY

I'm still not sure if this is the path i'd like to venture- but it helps knowing that this is an alternative.

Regards
Jack

 

[stuart45]

Thanks for the update Jack. Depends what Building Control think about it.
The practical side may be a bit tricky sliding the lintel out and in again to the rebar. These jobs often look a bit easier on paper.

 

[jackthehat2]

True indeed Stuart- that's the problem in the trade as well. It always makes sense up in the office on pc/drawings, but down on site it's a different story. And the somebody need to explain why the job took twice as long as what they "calculated"

I'm hoping that the rebar would flex slightly to allow for the angle that the smaller lintel would need, but then again it might not.

Still pondering on how to go about it- but a steel lintel would simplify things incl the Bco.

Atm there's enough to keep me busy- but will update when push comes to shove.

Regards
Jack

 

[jackthehat2]

Had the acros delivered on Friday and thought i'd have a go at it the weekend-

So far so good- just need to watch the weather now & catch a good day to get the outside done.
Quick question on the steel lintel- i've emailed catnic with the details for selecting the lintel and they came back with a heavy duty 60kn lintel... Does that sound right?
Would have imagined a 21kn lintel (L1/S75) http://iglintels.com/lintels/standa...ter-leaf-lintels/standard-load-lintels/#L1S75 would have been more than capable for the job intended?

Sorry for the picture quality-

Untitled

• jackthehat2
• 3 Mar 2014
• 1

Untitled

• jackthehat2
• 3 Mar 2014
• 1

 

[stuart45]

Try IG and see what they come up with. What did the Bco think about the other idea of rebar in the lintels Jack?

 

[jackthehat2]

Hi there Stu-

I'll fire an email to Ig in a minute or 2 and see what they come up with- but really can't see a load of 60Kn over 1.8m length

To keep things simple I've decided to go with the cavity lintel-phoned Bco up to see if I can add the enlargement to an outstanding application and they we're happy to combine the 2.

Regards
Jack

 

[jackthehat2]

Was meaning to update the post with a picture of the lintel in place but didn't get to it.

Lintel in place and bricked up- still waiting for the window to arrive before making an appointment with Bco to come & inspect it.

Regards
Jack

Untitled

• jackthehat2
• 16 Mar 2014
• 1

 

[stuart45]

Looks a really good job Jack, could of been done by a pro.

Out of interest, what did the Bco think of the young engineers idea of joining the concrete lintel.
Also what did IG say about the heavy duty one.

 

[jackthehat2]

Hey there Stu-

The professional look would be down to the bricky
I tried doing the brickwork myself but had to take it down as I wasn't happy with it- especially the outside brickwork.

To be honest I didn't even bother with putting the lintel extension idea to Bco- doubt they would have entertained it. I'll deffo ask the chappie when he comes over to sign it off though.

Spoke to Simon at IG and gave him the measurements and he came back with a calculation of 13.5Kn & told me the 21kn would suffice.
Might have been miscommunication between catnic & myself.

Thanks for all the help and advice.

Regards
Jack

Ps: You any good at tiling Stu?
//www.diynot.com/forums/tiling/sub-floor-preparation.396803/#3056738