Timber Windows - How to fix in place

[LeanTwo]

I'm taking delivery of two double casements, double glazed windows, which have wooden (Accoya) frames.  They are replacements for 30-year-old windows which are now largely filler!  They are to be fitted into the existing aperture.  The wall construction is a standard cavity wall, with Thermalite inner leaf, 100 mm cavity and concrete block outer leaf.  The outer leaf is faced with random stone (sandstone and flint mix)  at an average of 150 mm thickness, with a lime based mortar.  The existing windows are fixed to the outermost random stone facing and appear to have been fixed by nails driven through the jambs.  This seemed rather a crude way of fixing my new and expensive windows!  I intend fitting the windows to the outer random stone facing layer.

 

I have been advised that I could use concrete screws through the jambs into the mortar (being careful not to distort the frames) after having positioned the window with wedges.  I have also seen something called a frame tie in my local builder's merchant's catalogue, which is a piece of mild steel with a 90-degree bend in it and holes drilled in it.  Is this something different or could I use these to fix the frames to the concrete block leaf?

 

Also any advice on sealing the window frame in the aperture?  Are there particular fillers that I can use?  Should I finish off with a mortar on the exterior of the filler?

 

Thanks in anticipation!

 

[jamiehamy]

If you need any frame fixers please let me know - I've got rather a lot of them,  would need to check the pattern. The holes in them are more suited to putting into timber tho. 

 

I've used concrete Screws and they are a bit of a blunt instrument,  I wouldn't want to use them on a window frame. Would be better using a long Fisher fixing through the jamb and screw it in - less brute force and more discrete. 

[LeanTwo]

Thank for your reply and the tip to look at Fischer fixings.  I've been on their web site and they look good. Screwfix seem to do some good screws as well (as you might expect, given their name!).

 

Any thoughts from anyone on the type of fillers to use or the idea for a mortar outer seal?

[jamiehamy]

We used Compriband tape round the outer perimeter https://www.dortechdirect.co.uk/tremco-compriband-tp600-8mm-15mm-gap.html , expanding foam in the middle (https://www.dortechdirect.co.uk/illbruck-fm230-professional-expanding-foam.html) and then an air tightness tape to seal between the frame and wall. http://www.ecomerchant.co.uk/walls/airtightness-products/airtightness-tapes/pro-clima-contega-solido-sl.html There are any umber of products out there that can be used but gives you a flavour

[LeanTwo]

Thanks for the links. the three system approach looks good.  With the outer expanding tape, I guess the trick is to make sure the tape is the correct spec to fill your expected variation in the gap between the frame to the masonry aperture? For random stone, this could be quite a lot.  The inner sealing tape would appear to work well if it goes from the frame to a surface such as a concrete block or Thermalite?  It might struggle if the masonry surface is random stone?

 

With such a comprehensive system, is it necessary to have a dpc under the bottom edge of the frame?

 

One of the videos showed a window fixing bracket used to go from the frame to one of the cavity wall leaves.  Is this an alternative to a Fishcher/Screwfix type of approach?

 

[craig]

Just a quick note, the FM230 is now discontinued by Illbruck who only sell the FM330 now. You may still be able to buy it from retailers but not directly from Illbruck.

 

The TP600 is a good tape but if you can use the TP602, it will mean you only need one product rather than two and does the job of tape (membrane), compriband and foam.

Edited July 28, 2017 by craig

[LeanTwo]

Craig,

 

Thanks for the reply.  I'm interested to know how the TP602 works.  I'm guessing it's an expanding tape that forms such a good seal that the "middle" foam filler is not needed?  The inner sealing tape is still a good idea though?

[LeanTwo]

Craig,

 

I could only find the following link to TP602, which was in German.  Do you have another link, please?

 

http://www.illbruck.com/de_DE/produkte/produktfinder/product/tp602-illmod-max/

Edited July 29, 2017 by LeanTwo

[craig]

Sorry my bad, I meant to type TP652.

 

http://www.illbruck.com/en_GB/products/product-finder/product/tp652-compriband-trio-plus/

[LeanTwo]

Thanks, Craig.  Will this tape does away with the need for an expanding foam filler?  Will I still need an inner sealing tape?

 

[craig]

Does away for the need of expanding foam and membrane tape internally.

 

Its basically 3 products in one.

[PeterW]

@craig have you got any suppliers or ballpark prices ..?

[craig]

Illbruck will only supply direct to suppliers, Im not sure who exactly but I can give you a cost on Monday if you like?

 

 

Edited July 30, 2017 by craig

[craig]

On 7/29/2017 at 23:04, PeterW said:

@craig have you got any suppliers or ballpark prices ..?

 

@PeterW for TP652 88mm depth and expansion 8/15mm you are looking at £9.58 per metre, it comes in 6 metres rolls, roll cost would be £57.49 excl. VAT.

[jamiehamy]

I found Dortech pretty helpful when I ordered from them - they don't list TP652 but I would imagine could source it no problem.  https://www.dortechdirect.co.uk/tremco-compriband-tp651-trio-3-7mm-35mm-15-metres-2.html