Secondary Glazing In Collins Houses

Here are the details of the materials and suppliers we used last year when installing secondary glazing in our home.

We reviewed various solutions prior to making our decision and this system remains not only the cheapest, but also the most discreet option.
Panels are easily stored under a double bed during the summer months and offer an effective seal affording excellent thermal and acoustic insulation.

Modern acrylic panels have come a long way with guarantees in place on most products against cracking or yellowing for at least 15 years. Acrylic panels also keep the windows behind cleaner for longer and large panels are far easier to clean. Also, acrylic doesn’t shatter like glass, meaning it’s perfectly safe with children and animals. …I should be on commission here!

To secondary glaze every window in the house using this method took us about a day to complete. You’ll see from these details that the panels were professionally cut locally. On delivery of the panels, we applied the metal adhesive tape to our windows and then stuck the magnetic tape to the new acrylic panels. We used double-sided foam glazing tape to take out any undulations in the Collins frames. Very easy, just takes a while.

I measured each window, allowing at least 1/2″ of space on every side of the secondary glazing panel. Any less and you’ll struggle to get the panels off easily as the magnetic seal is quite strong.

This is our lounge bay window with three acrylic panels in place


The panels easily lift away leaving the thin, white metal strip behind. I believe this strip can be painted if required.


Magnetic tape
This is the magnetic tape stuck to an acrylic panel.


French Windows
On our French windows, we used standard sticky white insulation tape to create a seal along the threshold. Works perfectly!
Foam tape
You can see here how several layers of the double-sided foam tape can be used to take out undulations in the window frames for a good seal.



  1. 1)  12mm (1/2″) white foam double-sided tape
  2. 2)  12mm (1/2″) magnetic tape
  3. 3)  12mm (1/2″) white steel tape

£0.30 per metre £1.50 per metre £1.50 per metre

All of the above items can be purchased on eBay. Prices given are a maximum cost and include VAT and delivery. Order everything from one supplier for big savings!

4) Acrylic Panels for every window on our 3 bed home: £510.85 Total project cost: £700

Includes, delivery, VAT and all expenses


  •  When you remove the protective plastic film on the acrylic panes, give them a good wipe over with glass cleaner (we used Mr Muscle’s glass cleaner and it worked perfectly). The process of removing the film seems to create a static charge. Or perhaps it’s a small amount of adhesive left on the panels? Within a month we had to take them all down and clean them as dust was sticking them. Mr Muscle fixed this, as the problem didn’t return.
  •  In retrospect, I would have used the white foam tape on every steel strip. The metal tapes are mostly fine, but some are beginning to come unstuck. Collins windows aren’t great at being 100% flat and I believe this lead to a few too many issues getting the panels to fit perfectly. The foam tape is still as good a year on and the adhesive seems much stronger.
  •  A white clip-on frame is available for the acrylic panels which hides the white sticky tape on the panels and apparently makes it easier to remove the panels.
  •  Spiders like the protected void between the panel and the window. I assume they find their way in through gaps in the draughty windows. Both Phoebe and our cats seem to enjoy the ‘insectarium effect’.
  •  Some brass window furniture may get in the way of fitting the panels. We removed and heated the brass lifting handles on our sash windows allowing us to bend them back 1⁄4”. They still work fine and the panels fit!
  •  We used to get a lot of condensation on bedroom and bathroom windows and this has almost totally gone since fitting these panels. The better the seal, the better the reduction in condensation.
  •  Mark all your panels! The windows may look the same size, but mix them up and it’s a nightmare when it comes to refitting them. Pencil works well on the magnetic seal.
  •  Some ends of the steel tape have developed tiny signs of corrosion on some of the the bathroom / kitchen panels. This cannot be seen unless the panel is removed. Order extra steel tape as it may be worth replacing some strips after 3-5 years.
  •  Make sure French door panels and larger windows are made with 5mm rather than 3mm thick acrylic. The magnetic tape is still strong enough to take the weight and 3mm is just too flimsy for anything over a couple of metres.Summary:Our home is significantly warmer and easier to heat-up now these panels have been fitted. The sound insulation is significant and loosing all those draughts has made this project worth every penny. We’ve had this system fitted for over a year and certainly have no regrets.


Share: Facebooktwitterredditpinterestlinkedinmail

4 thoughts on “Secondary Glazing In Collins Houses”

  1. Please could you share the details of the supplier for the acrylic panel. Was this also ebay or did you purchase it more locally? I have found Gap, Formerton and Aamari by doing a google search. Do you recommend any of these?
    Many thanks for you advice and help with this.

  2. I can’t answer directly on behalf of Nick. We’ are in contact with him to update this.

    Meanwhile I did find a good online supplier who do polycarbonate rather than acrylic and I have a couple of sheets from them. They also do different fixing systems. They are very helpful.

  3. I bought my panels from Formertons now gap many years ago. At the time we had to buy a large sheet and they would cut it to size. We felt it was good value and it has certainly lasted. We bought Multi pole magnetic tape from “Indigo”. A neighbour told me that they will send samples so you can see what you are buying before having to commit


Leave a comment