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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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    • CommentAuthorgravelld
    • CommentTimeMay 13th 2019
     
    I think this is the correct tape to connect window to a masonry wall. I have block and brick cavity walls. The tape can be plastered over.

    What I'm not sure about is how the bare wall should be treated before application. In the application guide (https://proclima.com/products/bonding-agents/contega-solido-sl/application-guide) the walls have a white covering. So I assumed they must be primed somehow, but I couldn't find where it's documented how to prime the walls.

    This made sense - block in particular is very leaky.

    Meanwhile at this link (https://pycsystems.co.uk/pro-clima/pro-clima-tapes/) it says:

    "CONTEGA SOLIDO SL is bonded back to the existing block and can be easily plastered over the top of the fleece side."

    This makes it sound like it can just be stock onto bare brick/block.

    I'm minded to think that the airtight layer comes from the plaster over the top merging onto the tape which is stuck to the window.

    So is there no priming required?
    •  
      CommentAuthordjh
    • CommentTimeMay 13th 2019
     
    Posted By: gravelldSo is there no priming required?

    On the Pro Clima page you link to it says: 'Before adhesion is carried out, subsurfaces should be brushed off, wiped clean with a cloth or cleaned using compressed air. Uneven mineral subsurfaces may need to be levelled with a smooth finish' and 'It is your responsibility to check the suitability of the subsurface; adhesion tests are recommended in certain cases. Pretreatment with TESCON PRIMER is recommended in the case of subsurfaces with insufficient stability'.

    So the answer is as it says. You can ask Ecological Building Systems if you're still not sure. FWIW I believe that a concrete surface is generally considered unstable enough that priming is required (because of possible dusting of the surface). I don't know about block and brick, but I suppose that's why they suggest tests. Perhaps easiest just to prime it and have done with it.

    The airtightness comes from the adhesive junction if it is stuck to some material that is itself airtight. The junction to wet plaster is also airtight.

    Think about how you are going to attach the tape to the window and where the fleece will be to decide whether it is the best product. Also consider the detail at corners. In our case we stuck Profil to the windows and then stuck Contega PV to the Profil. But we didn't have a solid surface like brick or block.
  1.  
    +1 for primer and Profil tape.
    • CommentAuthorjfb
    • CommentTimeMay 14th 2019
     
    It will stick on to blocks fine without any primer.
    • CommentAuthorgravelld
    • CommentTimeMay 14th 2019
     
    Thanks everyone.

    At https://proclima.com/products/bonding-agents/tescon-primer-rp/application-guide/image-gallery-application-guide-620 it says:

    "Also mineral substrates such as plaster, concrete or similar. are primed with TESCON PRIMER and then bonded securely with TESCON VANA."

    This makes it sound like the primer makes VANA possible for window -> masonry (with caveats about not being a corner tape) and therefore CONTEGA SOLIDO SL isn't required... which in turn implies the primer isn't required, because what would be the point of the CONTEGA SOLIDO SL product?

    TESCON VANA is cheaper than CONTEGA SOLIDO SL, although with the primer too I'm not as sure.

    Ooh, also just found this diagram: https://www.greenbuildingstore.co.uk/products/which-airtightness-product/ which shows tape on the bare block.

    I guess call the distributor.
    • CommentAuthorgravelld
    • CommentTimeMay 14th 2019
     
    Posted By: djhAlso consider the detail at corners. In our case we stuck Profil to the windows and then stuck Contega PV to the Profil
    Why couldn't you just use Profil?
    •  
      CommentAuthordjh
    • CommentTimeMay 14th 2019
     
    Posted By: gravelld
    Posted By: djhAlso consider the detail at corners. In our case we stuck Profil to the windows and then stuck Contega PV to the Profil
    Why couldn't you just use Profil?

    Because the plaster is the main airtightness layer and I wanted to be sure of the bond.
    • CommentAuthorgravelld
    • CommentTimeMay 15th 2019
     
    Ah yes, I see Profil just says "Can be plastered over", whereas Contega PV:

    "PET fleece, easily embedded in plaster, no further plaster reinforcement is necessary".

    I'm learning so... were you just trying to minimise initial problems applying plaster, or were you trying to ensure the bond long term?
    • CommentAuthorgravelld
    • CommentTimeMay 15th 2019
     
    I was also wondering about onsite "adhesion tests". I found this great resource:

    https://proclima.com/media-download/333/pro%20clima%20in%20depth:%20adhesives.pdf

    I might misunderstand but the test referred to being in "box 1" isn't there - there is talk of a water test though to judge surface tension.

    What sort of onsite adhesion tests do you carry out - just trying the tape, leaving it a few hours then seeing if it peels off?

    As the above link demonstrates, adhesion improves for many hours after sticking.
    • CommentAuthorgoodevans
    • CommentTimeMay 15th 2019
     
    I've just used it and it sticks fine to the blocks. I am also using it behind cables/capping on external walls - just the boxes to seal with some form of gunk.
    • CommentAuthorgravelld
    • CommentTimeMay 15th 2019
     
    Thanks!

    I spoke to EBS today and they were extremely helpful, I'm just tidying up some questions with them and will report back.
    • CommentAuthorgravelld
    • CommentTimeMay 17th 2019
     
    Having discussed it, I'm thinking the easiest solution for us will be:

    - Remove window, cut back plaster to a depth to (almost) exactly accommodate the new window depth. Replaster over top of new straps.
    - Tape from window to plaster using Profil
    - Finish with insulation board over the plastered and taped reveals

    If the wet plastered reveal is smooth and dust free then I don't need a primer.

    One reason for using Profil over Contega Solido is the folded element is much narrower for the window face, so you can be sure there's space for the tape on the window and means the insulation board doesn't need to be so deep.

    Any unevenness in the area between the plaster and the window can be filled with a sealant and then taped over.

    Contega Solido SL is definitely fine for taping direct onto smooth mineral surfaces, but naturally these have to be cleaned down.

    For the dry lined reveals, for which there is no real AT layer, I'm thinking to prime the block, tape to the primer, then just leave it, hoping that one day I'll be able to get rid of the plasterboard and plaster over the tape. At least in the meantime we've done what we can to lower infiltration from immediately around the window.
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