For many decades, silicone has been the material of choice for the sealing of windows and doors in the UK. It comes in many colours, it’s easy to apply providing the guy holding the gun knows what he’s doing, and it’s convenient. Yet silicone is easily one of the most inefficient products in the whole window and door installation process.
High U-Values
The industry has been doing a sterling job of making the window frames and the units that go into them much more efficient than previous models. U-Values have dramatically reduced and WER’s (if you believe in those) are massive right now too. Yet, an area which seems to have been ignored is the opening new windows and doors go into.
We’ve focused so long on product, that we have ignored what the product actually goes into. Traditionally, a window is fixed to it’s opening through screws, then foam, then silicone sealed. Yet all of those materials are incredibly inefficient when it comes to insulating, and the U-Values are ridiculously high when you compare it to an A rated window.
As far as other European nations go, namely Germany, Austria and Scandinavian countries, we’re very backwards int he way we seal windows and doors. The idea of silicone is old fashioned by decades and sloppy. So what is the solution?
Expanding sealing tape
What seems to be gaining traction, albeit slowly, is expanding perimeter sealing tape. This is a compressed foam based material that is applied to the outer edge of the window and door, with a tape. When the tape is removed, the foam tape then expands. Once the window and door is fitted, the foam expands to compress against the outer edge of the brickwork, filling the gaps, giving a weatherproof seal and a much warmer, energy efficient seal.
It’s easy to fit too. Check out this promo video from Iso Chemie:
The foam expands in a relatively short space of time, and the finished article looks great inside and out. Much neater than silicone.
Importantly though, the U-Values and energy efficiency of this product are hugely reduced compared to silicone. And, it feasibly reduces the need for trims, at least externally. So in a cost comparison, the end result might be that this perimeter tape is only slightly more than it costs to seal up a window with trims and silicone.
Obvious USPs
The product sells itself. A warmer, easier to install solution for installation companies means a better and warmer overall job, with less time spent on site. The black colour works with almost any frame type and colour. No need for artistry with silicone guns either.
But will the UK market adopt to this? We do see some forward thinkers on social media that show off their work with this sort of product, and it looks great. But we’re notoriously difficult to evolve and change in this market in the UK. Fitting crews used to silicones will probably be the hardest bunch to convert. It’s easy for us sales guys to promote though.
We will end up ditching silicones? Probably, but many years down the line. There will be plenty of silicone suppliers hoping this change will hold off for as long as possible!
As always, all comments welcome in the section below.
This blog sort of follows from my comments on salespeople. All sales people should be mentioning this to up sell product.
Like when you buy a car, do you want the standard wheels or do you pay extra for a different design of alloys. Car sales man will ask the question. Cost to manufacture is about the same but dealer can charge £1000 +
These tapes do look great for window installations…Iso-Chemie is a company that has impressed me with this type of product. I am not sure if or how they will be used in roofs, where for example we use a lot of co-extruded gaskets as the primary seal backed up with tube applied MS polymer or low modulus neutral clear to give a ‘belt and braces’ approach.
Structural glazing on multi storey buildings is weatherproofed with special sealants – it works there and is well proven technology.
I’ve used this type of tape in my commercial days ( 20yrs ago ) then at last years fit show I bumped into Tremco offering enough tape and help with installion free . Great I thought, signed up. We had a big R9 in stone job upcoming.. Idea ,the lads from Tremco came along, showed us the little tricks and wow what a result . The installation was for a committee led village hall . Sign off day arrived .. The committee led elders were not so impressed:-( . And nothing we could say would change their minds, we ended… Read more »
Oh come on DGB , that is a ridiculous scenario , having watched the film , the building is made of biscuit bricks which are laid straight across the reveal , transferring the heat/cold from in to out or vice versa, what difference in u-values this tape offers is beyond me. You even criticise the screws we use , yet a nylon sleeved anchor is a better insulator than the bolts they show in the film. The building shown is a new build clad/rendered affair , marvelous , if that was a standard fit , then sell it every day… Read more »
I’ve been using a similar tape for years in the EWI trade. The tape we use is only 10/12mm wide and might expand to 10mm. It is super floppy, stick to anything bar what you want it to stuff. On the cliff face, we tend to stick it to the piece of insulation we are fitting. There isn’t time to stick it on the subrate. If the sun is shining that tape is expanding from the second you cut that tape. It is the last thing we do, but some of our insulation panels are dusty after cutting and the… Read more »
This tape takes 2 hours to expand from 2mm to 12mm (if needed) the tapes you are using on EWI work expand very quickly, this one doesn’t. Kevin-it may seem a ridiculous scenario as the video is for a German installation-It is being used in the UK perfectly well-it works on all window materials into all building materials and has a guaranteed minimum U value of 0.8W/m2K. It is also guaranteed for 10 years which I doubt any silicone installer would match. Try some!
I am sure that in many new build scenarios the product works great , but as BWF points out , it doesn’t look finished , the video shows a rendered/clad building , then great , you wont see the stuff , but in the standard replacement market mastic and/or trims help make the job look finished. I might try some though I am unsure of the benefits of the stuff, the USPs DGB suggests don’t add up to me , besides , I personally think that having a crew who can actually apply silicon in a neat and tidy fashion… Read more »
Tell you what, Kevin-I will give you a roll to try-I also have many photos of Uk installed jobs where the ‘black line’ (it is only 5mm in the uk) matches the black spacer and bead gasket perfectly. It also makes the frame perfectly straight, ensuring it looks as slim as possible. the fact that it is so easy to apply also ensures that all finishing jobs are of the same standard. (you will be good at siliconing but if I were to do the same job, it would look awful) Pls send me details at a.swift@iso-chemie.co.uk. and I will… Read more »
I looked into the Iso- Chemie tape a couple years ago and it is far from simple to use on an everyday basis. Great product. Great idea. But has several issues that will perplex and frustrate the installer. Had that not been the case, we would be using it on all our installations now………….
Ok I shall be in touch , I may even do a review ;)
@ Paul I can see any number of issues even from the video , and really see the only advantage of it is in new build prior to render or cladding , but even then , we would normally use a cill , so how do you wedge the frame in the opening with the tape all around it ? 2 hrs to expand is a long time to be hanging around to be told the frame still needs pointing. I must say if it was such a no brainer, why is the whole industry not beating down the door… Read more »
Paul-what were the issues?
Kevin-It takes 2 hours if expanding from 2-12mm. As the uk gap is more like 5mm, it would expand in 30 mins or so-it will be quicker in hot temperatures or you can accelerate the expansion with a heat gun
It can be put under the cill or left off the bottom section altogether-depends on how you point around the cill normally
When I first introduced composite doors, they were trounced as being a ‘never going to happen’ part of the market-now look at them! The industry takes time to change-
No problems AJ I will get some from you and try it ,
But just an observation if I may ,if I need a heat gun to speed the process, it is slowing the fitters down surely , and if it is OK to leave it off sections of the perimeter then why use it at all ?
I know I sound bit pedantic , but what are the benefits for a standard UK replacement fit ? , DGB mentioned USP’s, but I am not sure he actually came up with any :)
Hi Kevin There are various sizes you can use-so if your gap was 5mm, you would use one that started at 3mm-Some timber installers use 10mm gap so they would use the tape starting 5mm thick It expands slowly enough to get the frame in but quick enough to have closed the gap by the time you have finished the job The warmer it is, the quicker it expands features and benefits, thus 1-Insulates the gap to at least 0.8W/m2k -matching or beating the window u value and retaining energy 2-reduces sound intrusion by 63db- equivalent to a vacuum cleaner… Read more »
Thanks Andrew
I will give you points 1 and 2 , the others , not at all sure just yet , I can see an issue with cill horns , they will need finishing off , if the frames are not pointed to brickwork , how do the cill horns get finished? A rhetorical question I guess for now , but just another to muddy the waters ;)
My main issue was handling by the installers. Waste if tape not stored correctly and kept cool in back of van. Partly used rolls can deteriorate very quickly, hence Citizenbrians expanded rolls in the debris. And that’s not cheap! There were several issues. If these could be sorted, then I’m interested, but I can’t see how. Maybe a fine grade expanding foam with reduced flatter nozzles for small gap input and then trimmed over to protect from UV might do a similar insulating/ noise reduction job?
The small flexible plastic tubes you get with the foam guns (or at b&q/halfords) slide into the gaps around a frame quite easily , a careful squeeze and the frame is bedded in , I wouldn’t regard this as ‘finished’ but then I am yet to be convinced that the tape detail is ‘finished’
Paul-I dropped a bit of our BLOCO one in to you today to try-whatever product you used last time may not have been ours as I have no record of you ever buying any from us?
Hi Andrew , sorry I could not get back to the office for you , Paul apologises for being a bit ‘quick’ with you but I hadn’t told him you might call in, he thought you were just a cold caller !!
Hey-no worries, Kevin! He was ok with me!
Hi Andrew I saw your comment on the other thread and it reminded me about your tape!! I have used the roll on a new build job for a very particular customer , it didn’t go as far as I thought , but that is not a criticism , just an observation that window perimeters eat up the metres quicker than you think! Now , application is a bit fiddley with the full roll , but gets easier as the roll gets smaller , getting the edge flush-ish with the frame edge can again be a little inconsistent to a… Read more »