Double glazing old sash windows. 

Thank you Neil. Greatly appreciate your comments.

Thank you for the comment. If you have any further questions please drop me a line.

Thanks Philip.

Thanks Tom. Hope it was useful to you.

Your welcome.

Thanks Douglas. Glad it helped and I appreciate the feedback.

Thank you. Appreciated.

I'm glad you liked the video. Take your time and enjoy.

Hello Nik Nat. I have some available if you are able to collect. Only a few sheets but please email me at warwickshoprenovations@gmail.com for more details. Kind Regards

Thanks for the feedback Adrian, myself and the subscribers will find this very useful. My glazier said it was not possible to fill these DGU’s with gas so I will ask around and seek more information. It would be beneficial if I can get a supply of gas filled DGU’s, I am sure there will be a supplier in the midlands who can do this. Also, good information on the warmedge spacers. Luckily for me, all the units I supplied in this house are toughened glass as the bottom of the windows are lower than 0.5m to the floor, so UK regulations state all glass must be toughened. Cheers Ed

@@warwickshireworkshop9186 You're welcome Ed . For the past 3 months I've been working on Grade II Listed properties and they would only accept the 4-4-4 Heritage units which have a warm edge spacer and filled with Krypton gas. You can fit them in an 8mm high rebate but the problem is they either last 20yrs or 2yrs and most companies will only give a 2yr warranty on them. They are also hugely expensive too at around £130 sq meter and you can only have them fairly small otherwise the panes can touch and you get what they can "Newtons Ring" which appears like a ring,halo in the middle.. All the best Adrian

Thanks Larry.

I'm glad the video was helpful Dave. Good luck with your restoration project.

Hello Chris. Thanks for getting in touch. Yes, steel pins are not the best. I've also damaged a few router bits on pins that broke in half when they were removed. That tell tale sign of sparks when you rebate the frame is not something I want to see.

Hello MRJTUK. Thanks for getting in touch and also for the positive feedback. I’ve not worked with laminated glass yet, so here are my thoughts. If I was fitting laminated glass, I would think about treating the window as a re-glazing project and not a double glazing project shown in the video. After all the only difference is the thickness of the glass. The width and height will stay the same as the glass removed. If your original glass is 4mm thick. You could either just drop the depth of the rebate in the frame to accommodate the extra 2mm and use standard beads or even easier - leave the frame as it is and just machine the beads so they are thinner. There might not be any need to remove the wooden separation beads. If you did, after the window is finished you will be able to see through the inner and outer wooden beads to the inside of the wood. It might look a little odd close up. Some options for you to use. Hope it helps.

Hello Beyonda1881. Thanks for the email. Regarding hard wood vs soft wood. Hard wood lasts longer but the original sash windows you see my video were made in 1928 and due to good paint application over the years they have lasted well. So don’t worry about the wood too much unless it contains knots. To rebate the glass into the wood I do the following. To get the depth, Take the glass thickness, then another 2mm for the silicon sealant (1mm between the glass and the frame and 1mm between the glass and the bead, then add what ever the bead depth is. You can change the thickness of the bead as shown in my video. I hope this helps and good luck. If you get stuck send me an email.

Hello Ann W. Your message is incomplete, could you resend and Ill get back to you. Many thanks.

Hello Marcdebattista. I hope you are well and thank you for the positive comments. To answer your questions, please see the following. 1) I have used tape to hold the outer beads onto glass and it has proved successful. I only use a 3M VHB tape which works well. However, I prefer silicone to bond the glass to the frame. 2) In my mind. Drilling holes allows water vapour and insects to get inside the wood (or block it up). I prefer to stop the water getting in in the first place. Attention to detail is the key. If the frame rebate is well painted a bit of water wont hurt. The problem is if it freezes when touching the glass, hence the 4mm gap. 3) Well spotted. It should be a 4mm spacer. 4) I use 14mm thick Double Glazed Unit (4mm toughened glass, 6 mm silver spacer and another pane of 4mm toughened glass). This was best for the frames that existed in this house. Anything thicker would look odd when looking at the window from the inside of the house as the flat part of the inner bead would have been removed. Obviously the thicker the DGU the better the insulation. You can also fill thicker DGU’s with inert gas that makes the insulation better. You cant do this with 14mm units, so my glazer told me. 5) They are quite thin in this case but I did not measure them so cannot tell you the exact size. I used hard wood for better weathering. I have used double sided tape to stick the beads to the glass but that only creates a bond between the bead to the glass. When using tape I relied on paint to cover the gap between the bead and the frame. It’s easier and just effective to use silicone for both points of contact. 6) If the frame contains old hard putty I would use an old router bit to remove it back to the frame. (It blunts the bit quickly) Then I normally start by routing out sideways to the width I require in small 2mm steps. Then drop the depth and repeat the process. Pay attention to bits of old glazing nails left in the frame. Sometimes, not all of the nail comes out. I hope this answers your questions. Please let me know if you have any more as I am happy to help.

@@warwickshireworkshop9186 Thanks a lot for your detailed answers, it is very helpful! I have since come across the 'THE B6 HEEL BEAD SEAL SECURITY GLAZING SYSTEM' from Hodgson (one of several solutions). They have very informative technical specs for different configurations (fully bedded, drained, new or retrofit). They pretty much illustrate the solutions presented in the GGF Glazing Manual. Have you come across these resources? Apparently the DG unit seal is prone to failure if the wrong type of silicone is used and their products shouldn't cause any issues.

@@marcdebattista Thanks for this. A colleague mentioned this to me last Wednesday but I have not looked at it yet. I'm not to worried about the degradation of the DGU seal as the silicon I use does not come into contact with it. So far, all my DGU's have lasted quite a few years without any problem. Cheers.

Hello. Thanks for the comments. Yes, no pins were used in this video. The same goes for all the glass in my wooden green house - all the glass is retained with silicon.

Hello Neil. Thanks for the positive comments, I am glad you liked the video content. To answer your question. For these windows I used the Dulux Trade Weathershield Preservative Primer +, which you can see being applied at 10:37 in the video. This primer is the first step in a 3 part system that Dulex offer and is about as good as you can get for old soft exterior wood. Here is a link: www.duluxdecoratorcentre.co.uk/product/paint/exterior-paints/exterior-trim/dulux-trade-weathershield-exterior-high-gloss/dulux-trade-weathershield-preservative-primer-bp However, on another recent job the customer wanted to change all the wood on their house from Brown to Black. I had to completely strip back the barge boards, soffits, window frames, windows and doors to bare wood. I then painted them with all with aluminium paint and then used a black metal paint as the final coat. I did this because you are effectively covering the wood with metal. So there is another option for you. Hope this helps. Let me know if you need more info.

@@warwickshireworkshop9186 cheers for that - exactly what I wanted to know. 👌

Hello John. Thanks for getting in touch and good question. Allowing the glass to sit away from the spacers would be preferable to allow for expansion and this should be possible as the silicon can support the glass in the frame. The aim of the spacer is to keep the glass from sitting or moving onto the wooden frame. This then allows any water that gets into the gap to stay away from the glass. You can use either what is shown in the video or any size gap and spacers you prefer depending on the size and shape of the wood. Hope this helps.

Hello Antonio. Thanks for getting in touch. Being based in Warwickshire I am sorry to say I am not familiar with companies in West London. From my experiance it is best to visit a few of them in person, explain what you need and gauge their reaction. If you can take in one of your sash windows it helps them understand what you are after. Some might actually measure up for you. Hope this helps and sorry I could not answer your question more specifically.

Hello Mark. The only rule is to use the minimum thickness double glazing possible which is about 14mm. This will then have a separating bar with a distance of about 10mm in form the edge. So with the 2mm surround gap that makes 12mm rebate all round. You will cut into the corner joints of the frame as I do. The depth you plunge will be 14mm + the bead, which you can cut down to size to minimize the wood removed. One thing to remember is that glass and esp. double glazing is very strong, it has amazing ridged strength capability. So if it is securely bonded onto the wooden frame with silicon it will become the strongest part of the window and keep the wooden frame together. Send me some dimensions of the frame you have if you are concerned and Ill compare them to the windows I have restored. Hope this helps.

Hello Alex ‘Sensational’ Harvie. Thanks for getting in touch and I’m glad you found the video helpful. Did you know there is a band with the same name as you? Back on track - You will need to board up the window once the sash is removed as it will take a few days to strip the frame, repair it, router it out, repaint it and put it all together. This will take over a week minimum allowing 24 hours for each coat of paint to dry (if the room is warm that is). If you take it out measure it and on the same day, send the details to your glazing company, the glass should be back with you before you have finished painting the frame. You could also take the whole unit to the glazier on the day you remove it, explain what you want and they will measure it for you. If it shows up wrong (it has happened to me) they will have to get another one made, costing you nothing. Again, the DGU should be with you before the frame is dry. Your house is more secure boarded up than it is with single pane glazing. I sometimes paint a window onto the board to make it look a little more pleasant esp. if it faces the road. The other way is to measure the width and length from the inside edge of the frame then ask the glazier to add on the dimension of the separator bars so the full width and length of the DGU is the dimension you measured plus the separator. This will then place the inside of the separator bar level with the wooden frame. Remember to router the frame out 2mm all round for expansion and 4mm at the bottom. Hope this helps. Any more questions feel free to email me. Thanks. Ed

Yes Mark. The Old glass is irreplaceable. All the old glass I remove from my windows I pass onto a specialist window renovation company who come to the house and collect it. It is that important to them as you cannot get it any more.

@@warwickshireworkshop9186 However I have found a supplier that imports 3mm glass for greenhouses so all is good.

Hello Lilla. Thanks for getting in touch. Can you share a picture? Without seeing the windows, I would think that the biggest issue would be rebating the frame to allow the DGU to be installed. If you cannot get a router deep enough into the wood, then whoever does this will have to use a chisel to rebate the frame. If the window does not have any Muntins, i.e. only made up of one single pane it would be possible to do in situ. Otherwise - if it went in - it can come out, it should be removed on that basis. Sorry I have no magic wand to help.

@@warwickshireworkshop9186 Thank you very much for your quick response, you are a true gentleman! My biggest fear is that the muntins are too slim and they are rebated. I have successfully replaced single glass panes in our front door with stained glass but that was child's play compared to this. My windows are like this (these are new windows in the pic) except there are two fan windows (8 panes altogether) on the top and only one wing opens. www.homeadviceguide.com/wp-content/uploads/2013/09/wooden-windows-cost.jpg

@@lillahamvas9700 Thank you for the picture. Without looking in detail at the actual window. If I was to work on the window in this picture, I would suggest you remove the 3 panes of glass and the 3 muntin’s totally. You then have a choice. Fit one single DGU and have it look like one pane of glass or ask for dividers installed in the DGU where the muntin’s were and stick on external glazing bars (Pieces of wood) to cover the gaps between the internal dividers. This will make it look like it is still 3 panes of glass. Depending on how small the fan windows are removing the muntin’s will let in more light and might look OK without the 8 panes of glass. I would still try to remove the one that is fixed, it should come out.

Hello Daniel. Thanks for getting in touch and for the positive comments. Appreciated. I cut a sheet of 11mm OSB down to size, paint it white and screw it into place. If the window faces the predominant direction of wind and rain I add a bit of clear silicon for draught and water protection. I paint the OSB white as it looks better than plain OSB. If I had any artist skills I'd draw a sash window and a pot plant on it but thats beyond me. Hope this helps.

Hello Joe. Thanks for the message. Silicon is extremely strong so nails will not be needed. I would think you might have to deconstruct the mullions and by using a router table, reduce the depth of each one then stick them onto the DGU. If not make a jig to support them while you use the router. It will be painstaking work but with patience it should work. I have not used this method on French doors even though I have a set in the house. Let us all know how you get on.

Hello And Rew. Thanks for the positive response and I am glad you liked the video. I don't normally endorse tools, equipment or companies as I want the viewers to get an unbiased and honest review. But as you asked the question here is the information. This price of this particular unit just crossed into the 3 figure mark. The company I used was Northfield Glass in Birmingham.

@@warwickshireworkshop9186 That's brilliant, thank you very much!

@@warwickshireworkshop9186 good video, awesome of you to share the process, so around £100 ish for each double glazed unit is good to know, thanks, keep 'em comin'

Hello Jason. Thanks for dropping us a line. It is easier to fit one piece of glass than it is three. You will have to create a gap between each DGU so would run out of wood to hide the separator bars behind. Hope this helps.

Hi Bel. Thanks for your message. As the Double glazed unit in these windows is thinner than the normal upvc DGU's the efficiency is slightly less, if you are just comparing DGU's. I'm not sure about the U Value so cannot comment. The cost of performing this piece of work to having the original sash windows ripped out and replaced with plastic is far cheaper and you retain the looks, so yes, that's why I did it. The house shown in this video is the only house in the road that still has the original windows. Even by hiring a decorator every 5 years to paint the outside in order to maintain the wood, it would take decades before you reach the cost of UPVC replacements units. Hope this answers your questions.

@@warwickshireworkshop9186 yes, that makes complete sense. Great work

Thanks for the email Andy. Greatly appreciated. To add 4 separate panes to one frame would be 4 times more difficult due to alignment. Managing one large pane is easier than 4 separate ones. Also, the width of the metal edge separator bars found in the double glazed unit are around a minimum of 12mm deep. That means a total of 26mm min (including 2mm air gap) that the wooden Muntins will need to cover. On all the windows I have seen there is not 26mm available so you will see the metal separator bars in tine double glazed unit peeking out behind the wood. Hope this helps.

Hello Mike. Thanks for getting in touch. The spacers you mention are there to segregate the sections of the window and the separation distance is dictated by the thickness of the wood they hide behind. In this particular frame there were 3 panes of glass, one lower and two upper. Without the spacers there to segregate the single double glazed unit the view you see at 13:49 in the video would be of the inside of the wooden spacers. IMHO not a good look. With the spacers the window looks like 3 double glazed units. I hope this helps.

@@warwickshireworkshop9186 Ah, got it. Thanks for explaining. It all makes sense now :)

Hello. No I dont, I use the Dulex Weathershield 3.2.1 system.

Hello Zirman. The original steel weights are normally cylinders of cast iron with domed ends. Adding anything to these is difficult as the space in the sash frame is limited. Lead is the only way to go if you are converting to Double glazed units.

Hello Mark. Thanks for getting in touch. You could do this but you would have to make sure the walls of the holes are treated to stop rot from within.

Hello Tom. Thanks for getting in touch. On the older sash windows built around the 1920's, the glass will be circa 3mm. So with regards to a 2 pane frame with glass measuring 550mm x 320mm each, the weight is 3Kg. I have a DGU measuring 555mm x 700mm so roughly the size you will use to replace the two single panes with the method shown in the video, the weight of this DGU made up of two 4mm thick glass is 7.5Kg. Hope this helps.

@@warwickshireworkshop9186 That still doen't explain why a larger gap means more weight?

@@eah4187 frame of DGU must weigh something and one would expect 4mm glass to be 33% heavier than 3mm.

Hi Ste25. You can use a normal double glazed unit but when you put the unit together you will be able to see between the Muntins. These are the wooden bits that would normally separate the original single pane glass sheets. It will look a bit odd close up but still work. Hope this helps. Cheers.

@@warwickshireworkshop9186 Hi thanks for the reply ,if i could just ask when routing the frame you have to take it down to a level to take the extra depth and beeding but do you have to also increase the width and height of the opening to avoid the edge showing or does the beeding cover it ?if so how is this calculated ? also do you have any risk of the unit failing and is there a way to minimise the risk of this happening ,sorry for so many questions and many thanks for your help.

Hello Ste25. Thanks for the questions, I want you to get this right so no problem in asking. The Double glazed unit (DGU) should have been made to a size that it has the inner edge of the metal separator bars (the bit between the glass) in line with the inner edge of the wooden frame. Then rout the wood to accept the glass width + 2mm at the top and side and +4mm at the bottom. The beading should run from the inner edge of the wooden frame and separator bars (The 3 should line up) to the newly routed width. As far as failing units, I have had no problem with this. DGU's are extremely tough and when the wood is glued to it with silicon the unit will be strong. Hope this helps. If you have any more questions, fire away. Good Luck.

@@warwickshireworkshop9186 hi thanks for reply, just a last couple of questions ,can you putty instead of using beading ?, also i believe you cannot get spacer bars for 14mm are yours 18mm ? and do you bother draughtproofing staff /parting bead etc if so what method ? thanks again for your time .

@@MrFlynn261 Hi Ste25 thanks for the questions. Regarding the putty, I have never used it but due to the distance between the edge of the wooden frame to the inner section of the metal separator bar you would be spreading the putty too thin. My glazing is 14mm thick for sure. it is the thinnest DGU I can get. To completely draught proof your sash windows you need to buy staff and parting beads. I use this company to get all I need. www.reddiseals.com/. They also do a neat little router bit that enables you to run a groove to the top of the upper sash and the bottom of the lower sash that you then run a plastic channel and draught proof seal. I hope this helps.

Hi Mike. I only use silicon to hold the glass to the frame and the bead to the glass. The void between the edge of the glass and the rebated wall I left open. I did this because sometimes double glazing fails and you end up with condensation in the void between the glass. If I filled the void with silicon id never get it all out.

Hi Rodney. Thanks for getting in touch. To be honest I don't know as I have never measured it. I am going back to a previous customers house where the glass has smashed due to an accident, When I am there I will measure up and get back to you. Hope this does not delay your project. However. 8mm does sound a bit thin but on the other hand it only has to stop the glass from falling out. If you are in the UK there is little risk of tornados or hurricanes sucking the glass out so you might get away with it. I would try mocking up a frame and then see how strong it is, I think you will be surprised.

@@warwickshireworkshop9186 I'm in Australia mate so I think I'm safe too but would be nice to have a bit more meat

@@rodneyjacome6117 Hello Rodney. I measured up one of the frames yesterday. I have 19mm left on the frame after rebating. So a bit more than double yours.. What's the depth of your beading. As you can see in the video I've skimmed mine down a bit and they hold well.

Hello Edison. Thanks for getting in touch. It depends on what paint system you are using and how fast your glazer can supply the DGU. Ignoring the removal of the old frame from the house and securing the aperture left by the unit and working to an 8 hour day. Lets start with the frame in the workshop. On day one. Measure the frame for the new DGU. Order the DGU. Remove the hardware, glass and strip the paint. If the frame is loose, apply glue to the joints and wood filler to any cracks. Clamp up the frame and leave over night to set. Order the lead weights for the heavier windows. On day two. Remove clamps and sand the frame to remove any excess. Check for any paint left in the difficult parts to reach. Set the frame up for routing and rebate the frame. Wait for the glass to be delivered - this takes a few days. Make the beading to fit. On day three. Depending on paint system. One day = one coat. So this depends on what system of paint you are using. Paint the beads at the same time. Next task. Fit the glass and the beading and apply the final coat of paint. In my experience it takes 7 working days for each frame. Most of this is watching the paint dry. Hope this helps.

Sorry for the late reply. With old single pane sash windows the weights are normally cast iron. These need to be discarded and new lead weights purchased. I weigh the completed double glazed sash then buy two lead weights that add up to the total weight of the sash. But to answer your question. You can always add lead to existing lead weights. Hope this helps.

@@edfranklin9561 You can add weights to sit above the existing weights. Weigh the new glazed sashes. Then add weights so that the top sash is marginally lighter than the weights to ensure that the sash will naturally draw up to the top of the window frame rather than tending to drop down. The bottom weights should be increased to be marginally lighter than the bottom sash to ensure the opposite. That is, the bottom sash being slightly heavier than its weights has a tendency to stay closed against the bottom cill

I'd Love to Jonathan, Unfortunately I am all maxed out currently. If you have a house that needs double glazing, can I suggest you try Mike Honour Windows.

Hi there Kino Recaps. Thanks for your question. To do it yourself and not including your time or any tool purchases, would cost no more than £140 in my estimation. But this is 2021 and prices are going up every day. It also depends on where you buy your products. My advise is to shop around, set up a business account if you can to max the discount and get a good working relationship going with the suppliers. Bigger is not always the best. Good luck in getting someone to do it for you. I failed so started doing it myself.

@@warwickshireworkshop9186 thank you for your reply, i‘ve had some crazy quotes for 8-12 k. I found all the tools and materials for £600 now ill get it done myself. quick question about the canal on the sash hoe deep should it be?

@@tateknows1688 Hello there. Yes they are crazy expensive. I was quoted £35K to completely replace 19 sash windows in a house once, hence this video. I am not sure I know what you mean when you mention the depth of the canal. If you mean how deep do you recess into the frame it will be the width of the glass plus the bead depth +1mm for sealant. Hope this is what you meant. If not feel free to email me on warwickshoprenovations@gmail.com with more information. Cheers.

@@warwickshireworkshop9186 thanks mate i appreciate it

Hello mingueyox. Thank you for getting in touch. The window frames in this video are a soft wood, not sure exactly what this one was but I assume it is pine.

@@warwickshireworkshop9186 Thank you for the quick answer. I am up to restoring and making new windows for an old cottage here in Ireland. Your video is very helpful. Cheers

@@mingueyox Your welcome. Hope they work out well. The key is a good paint finish. Try using aluminium paint as an undercoat with a metal paint top coat. I have just finished a house with these and in black - they look great. Best of luck.

@@warwickshireworkshop9186 oh, very interesting. To recap : etch primer, aluminum undercoat and a final metal paint. Right? Many thanks again

@@mingueyox no sorry. The video shows the Dulux Trade weathershield 3 coat system that has an etch coat to start. The other option is apply aluminium paint direct to the dry bare wood. Followed by a metal over coat. As aluminium primer paint is about 40% metal it's like coating wood with a metal coating. Very tough.

Hello Gerard, thanks for getting in touch and a good question. I would say yes, the retention properties of silicon are immensely strong. You have the silicon between the glass and the frame as well as the glass to the beads and beads to frame. I had to remove one glazed unit due to condensation and pushing it out was difficult. It only came out when almost all of the silicon had been sliced. I also have a greenhouse where all the glass is held in place using only silicon. In 18 years since I put it together, I have never had any glass blown out. Hope this answers your question.

Hi Steve. Thanks for your question. For these windows I used the Dulux Trade Weathershield 1-2-3 paint system. Its a bit of work to get it all on as it comes with a primer, an undercoat then a top coat which all have to be used in sequence. Hope this helps.

Thank you

The problem with that Graeme is that you need a 2mm gap around each glass unit. The original wooden separators on the frame would need to be made wider to cover the edge spacers. You would also need to keep all the glass aligned. It is possible what you say but a lot more work. Let me know if you try that method.

You will get a better U value for the window and improve air tightness by using a single pane, it looks pretty good and a nice renovation. IMHO loads better than Upvc.

Hello Richard. Thanks for the email. The original windows in this house had only one pane of glass in the lower section of the frame so this was a pure restoration project and the brief was to double glaze the original units which I did. You can see the original sash windows in the last few pictures of the video.