vivienz

How do I fill this gap?

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I have some recesses in my powerfloated slab that were put in when it was poured.  These were to allow the lift and slide windows to sit in the recesses and make the frame level with the finished slab and, indeed they are.  However, I now have 2 lift and slide windows where I need to fill the space not taken up by the window.  Any suggestions on how to go about this?

 

398991258_Windowfloorgap.thumb.jpg.96c09e1c5c20db030e565780b3a729ab.jpg

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Fill with concrete then cover with a wooden threshold strip.

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Difficult to make out the depth but either concrete or SLC if only say 5/6mm

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16 minutes ago, bassanclan said:

Difficult to make out the depth but either concrete or SLC if only say 5/6mm

 

Pardon my ignorance, but what is SLC?

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@vivienz self levelling compound I think....slc.   I had the opposite problem they made no allowance whatsoever for my lift and slides just sat them on top of the slab hence months of leaks.   Yours should be easy to sort and you at least have the drainage in place underneath as it should be.

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self levelling compound

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Thanks, chaps.  Just love all the little TLAs (three letter abbreviations).

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all carefully designed to confuse & exclude those not in the know..... 

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Vivienz, what's your final floor build up consist of on top of the concrete slab?  I'm hoping there's a degree of 'optical illusion' going on in this photo.....the slab height relative to the window unit looks somewhat 'marginal'?

 

Screen Shot 2018-10-08 at 22.05.08.png

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The floor is going to be something like amtico, so about 5mm plus adhesive.

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I've had some success with a 4:1 sharp sand or ballast / cement mix made up with neat SBR. 

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Posted (edited)
6 minutes ago, Ed Davies said:

SBR?

 

Like PVA...but better:

 

https://www.bal-adhesives.com/products/bond-sbr/

 

I've been using the Cementone one from Screwfix.

 

Dodgy slab edge:

 

2018-07-14_05-46-45

 

20180714_172832

 

Where I had to knock out the slab for some pipes:

 

20161215_192804

 

20161215_192832

 

20170105_190751

 

20170105_190718

 

No water in the mix just SBR, ends up like a resilient stone resin.

Edited by Onoff
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That looks good, Onoff. I will take some measurements and see what volume I will need. Quite a lot, I suspect.

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@vivienz

What's the provision for damp course / wet to dry transition from atmosphere to slab? 

I'd have thought the window fitters have done this before, but of all the level threshold stuff I've seen there has been a rubber type membrane that the window / door has been sat on which is turned down at the outside threshold and upstood at the inside. Do you have pics of before / during fitting?

My concern would be a too wet / runny mix migrating outward under the frame, so maybe the first step would be to inject a high expansion foam to seal, from the outside back through under the frame, and let that cure before back filling the slab from inside. Remember the airtight detail needs to be high integrity and last the test of time at these few junctions and that needs a plan, and a beady eye to execute it effectively.  👀

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Thanks, Nick. I will investigate tomorrow.

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@vivienz are the lift and slides Internorm? If so may have the tech data sheets for install.

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My gut feeling is the wet product shouldn't get to the frame at all. Foam for the bulk of the underbelly, cut flush and then a tape so the frame and whichever wet product is used will never convey anything to the frame. Assuming these have been packed and mechanically fixed, there will deffo be a void underneath and a path to atmosphere. Have the fitters detailed the outside of the frames at all at the footer? Pics please!

 

Remember that the frame will separate from the product ( SLC / other ) and airtightness will be lost. The frames need to be taped to the floor afterwards so you'll probably need to have tape continuing from the frame upwards to the underside of the threshold, and then a full width run of tape applied to the underside of the threshold but with at least an inch or so exposed ( so sticky side up ) so you can tape down onto that and the slab when the wet product has cured / dried fully.

 

It will be a PITA to do, but I'd try and remove the backing from one half of the AT tape ( 2" wide tape so 1" strip of backing removed lengthways ) so you can ( clean and dry first ) stick to the underside of the threshold and leave the backing layer protected tape showing 1" out ready to peel off and tape back to with the final 2" strip of AT tape.

 

Ultra SLC can be put down in 50mm layers, so I'd look to fortify that with 10mm aggregate and use that. That should ensure a void-free filler material and flow nicely into every nook and cranny. Beware, that if you leave a pencil sized gap under the frame its bye-bye SLC and it'll all just run out of the slab and onto the ground outside. Foam the 💩 out of it first ;)  

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I'm in site this afternoon so I will get some more photos and detail then.

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