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Please note: Most of the answers we feature here are from 1999 - early 2002. We endeavour to keep all links etc up to date, however if you spot any errors please let our webmaster know at It should also be noted that some replies may change in light of changes to legislation especially with regards to Planning Permission and Building Regulations. To submit a new question or to query an existing question visit

Question submitted by Simon

I have recently moved house and I have been told by the window installer that I cannot transfer the warranty from the previous owner without firstly paying a fee and secondly having the installer survey the property to check whether they are happy to transfer.

Is this normal practice? The manufacturer are well known, members of the GGF and offer a 10 year warranty. The windows were installed in 1997.

This question answered by the Windows Today editorial team - This is not that unusual - although we agree its a bit disappointing. Some companies charge 40 - 60 to do the paperwork - but this is the first time we have heard of them also saying they need to survey installation before allowing transfer.

We would pay the money - especially if they are a well known brand and members of the GGF. We would imagine its unlikely they would not permit transfer if you make the payment.

Question submitted by Bernard

I have continental style tilt-and turn uPVC windows. I am looking for blinds designed to fit in the window frame itself so that the blind moves with the window when it is opened. Who supplies such blinds?

This question answered by the Windows Today editorial team - Conventional blinds are not usually suitable for tilt and turn windows:

1. The brackets and fixings protrude into the room and are unsightly.

2. The brackets can interfere with window opening.

3. When the window is tilted into the room the blind dangles from the brackets.

These problems are overcome by using a virtually invisible tracked cassetted blind which becomes part of the window frame. This is the principal system used on the continent. It is manufactured in the UK by a company called INSU -

Unit 305
Harrow Road
E11 3PX
Tel: 0208 534 4073
FAX 0208 555 3870

Question submitted by Rod

I am looking for suppliers of windows which are wooden with upvc cladding to the outside, thus giving protection to the weather and the benefit of natural wood to the inside. I have come across Andersen from the States but are there any more?

This question answered by the Windows Today editorial team - As far as we am aware Andersen Windows are the only ones available in the UK with the upvc protection on the exterior face. There are some alternatives from Europe that feature aluminium and timber combined but not upvc. (Please note - this is as far as we are aware - there may be others - but if there is, they are not widely known.) Anderson windows of this type are only available as standard sizes. (Although there are over 6000 sizing options) They are ideal for extentions and new build situations.

One UK supplier for Anderson Windows is

Question submitted by Tony

I am considering having double glazing installed in an old terraced property which currently has sash box windows. Having received three quotes, I have also received three views on whether the whole sash box should be removed or the new units simply fitted within the existing sash box, leaving the internal wood surrounding area. One company said yes must be done for a good job, a second said no need to as the wood, probably the original, is OK and a third said doesn't matter, up to you, but fitting within the sash box will be cheaper. Is there a definitive view?

This question answered by the Windows Today editorial team - We are not sure that there is a "definitive view". It is true that both methods are used and there are many that consider leaving the original "box" in place OK. Complete replacement will be a fair amount more expensive and this is one of the reasons an "in between" option is often offered. We would always prefer complete replacement - but if cost is a consideration and the existing timber is "sound" then fitting within the existing box sash should be OK.

Question submitted by Teresa

I have had PVCu double-glazing fitted without any air vents. I have a huge amount of condensation and puddles on the window sill. Should the double glazed windows have been installed with air vents?

This question answered by the Windows Today editorial team - Fitting air vents (usually referred to as trickle vents) is required by building regulations in all NEW BUILD situations - such as extensions / new homes.

There is not currently a similar requirement for "replacement windows" - i.e. windows that REPLACE existing windows installed in your home. In our experience very few suppliers will suggest fitting trickle vents and indeed must homeowners do not care for the appearance of trickle vents in their windows.

Trickle vents will usually help reduce condensation. Fortunately they can be "retro-fitted". Expect to pay 15 - 20 per vent and at least a similar figure for fitting. Fitting may be cheaper if you have a lot done or much more if you only have one or two fitted. It's best to have the original supplier to do the work - but if they are unwilling try a local "Double Glazing Service Engineer" service. They will usually advertise in the small ads of local newspapers.

Please note that "Permanent vents" are often required in kitchens or places with gas appliances installed. These are very similar to trickle vents - accept that you cannot shut of the airflow.

Question submitted by Paul

I need to add trickle vents to my flat's woodgrain uPVC windows. Can you please suggest a supplier or manufacturer.

This question answered by the Windows Today editorial team - Just about any replacement window supplier or manufacturer should be able to supply you with "trickle vents". One "brand" we know are called "PVCu Solvents". These are manufactured by Greenwood Air Management (Part of Marly PLC) and while we doubt they sell directly to the public they may be able to put you in contact with a local supplier. They have a web site at

Installing Trickle vents makes good sense because they protect the building fabric from damp. Trickle vents are not usually very expensive - 15 - 20 each is typical - excluding fitting.

Question submitted by David

I had an extension to my 200-year old house completed last Summer, with custom made wooden casement windows and double-glazed units. The units were fixed into the casements with putty, whereas I now understand that this is not advisable. Will I have a problem in years to come and if so do I have any comeback on my builder?

This question answered by the WindowsToday editorial team with contributions from Brendan Bermingham - Double Glazed units are OK glazed in "putty" provided that it is with the correct "putty" which in this case happens to be a butyl glazing compound. Before glazing, the rebates need to be treated with a timber sealer and the units should be set on setting and location blocks. The void between the edge of the DG unit and the timber frame should to be filled with butyl before the beads are bedded to the glass and to the frame with butyl. Finally the windows should to be painted. (A good painter will paint 2mm onto the glass and form a painters line, which will protect the butyl glazing compound from drying out)

Please note however that if your builder glazed using linseed oil putty then the DG units will almost certainly fail prematurely.

Also please note that if your windows are to be treated with microporous stain then the above method is not suitable. There are many different ways of glazing timber windows and here is probably not the place to list all of them. Our explanation, is what should have been done for a "painted" window. If as I suspect your builder used only "normal" putty then I would suggest you get him back to explain exactly what he did do and any remedies he can suggest. Regrettably many builders and such still glaze double glazed units with "normal" putty - not knowing it is not really the correct way to do it.

Question submitted by Richard

Can a cat flap fitted into a double glazed door. I am moving to a new house and want to fit one there.

This question answered by the Windows Today editorial team - You don't say if what material the door is. We are guessing PVCU? Generally speaking fitting a cat flap into glass is not recommended (you or your cat are likely to destroy seal and the sealed unit may "mist up") Most people remove the sealed unit and fit a PVCU panel in its place.

Fitting a cat flap into a PVCU panel is quite easy and really not a whole lot more difficult than fitting in say a timber door. Most people do this themselves although we do know of some "double glazing doctors" (service engineers specialising in repairing replacement windows which are outside warranty etc) fitting catflaps on a regular basis. As of 20th February 2001 and excluding cost of cat flap most service engineer / double-glazing doctors would charge 40 - 60 to fit. (Some will have a minimum call out charge so don't be surprised if the cost is a little higher - although we have known of some charging less than above.) The challenge we find is - finding someone willing to do work - most Double Glazing companies are not interested - its usually only DG doctors / service engineers / handypersons who are interested in this work. Alternatively as we said earlier DIY.

Question submitted by Richard

I recently had double-glazed units fitted throughout my house. The method of installing the units was to cut blocks from the old wooden window frames, which had been removed, hammer these into the wall cavity, then screw the new units into them. The fitters told me this was normal and acceptable. I also discovered later that many window installers spray a foam into the space around the new units, where they meet the old frames. I was told this helps to stabilise the units as well as sealing them. The fitters did not use any spray foam on my house, but sealed the units to the surrounding brickwork with silicone. I would like to know whether either of these methods conforms to what can be regarded as good practice.

This question answered by the Windows Today editorial team - Both practices you describe are quite common. From your description we assume your windows are "cavity fixed". This means that at time of building the house, the original windows were fitted first and the brickwork was built around them. Clearly its not possible to repeat this process when fitting new windows and if the new windows are to be still fitted across the cavity area on replacement then something has to be inserted within the cavity in order to get a fixing. (Alternatively a frame fixing would need to be inserted at an angle across your new window frame and into the surrounding brick work - although this is often not practical and can loosen the surrounding brick work as well as being quite untidy).

In practice we would also say that the methods you describe are often combined in order to fit. Its important that anything inserted into the cavity is wedge just " tight enough" but not "too tight" or in such a way as to loosen the brickwork. With regards to good practice we have found that a number of variations and opinions on the above are common. All we can say is that provided that the quality of finishing and sealing are good and any trims fitted are properly fitted then you should not have any reason for complaint.

Question submitted by Ian

On a recent TV home improvement programme I saw some french doors that folded, concertina like, to give a wide unrestricted access to a patio. Unfortunately I fail to note the name of the company that supplied them. Can you advise a manufacturer that offers this type of product or can make them to order.

This question answered by the Windows Today editorial team - Try Sunfold Systems of "The Greenhouse", 93 Norwich Rd, East Dereham, Norfolk. Their telephone No is 01362 699744 We believe they mainly supply the trade - but they should be able to direct you to a local installer.

They have a web site at but at the moment the information displayed is limited. We like this product very much and the doors whilst more expensive than the "norm", are a refreshing alternative.

Question submitted by Jus

We recently signed a contract with a double glazing firm (not listed on your site). We asked the sales rep whether there was a 'cooling off' period to allow us to change our mind and cancel the order. He categorically confirmed that a seven day cooling off period existed. 24 hours later we decided to cancel our order and sent off the cancellation notice. We have today been advised that the cooling off period does not apply as we requested the sales rep to visit our house and because we are buying in cash the consumer credit act does not apply. Can you confirm / comment on this situation? Can you confirm whether there are any statutory regulations concerning cooling off periods?

This question answered by the Windows Today editorial team - Under the Consumer Credit Act you do indeed have statutory rights to cancellation. There is conflicting information for "Cash Buyers" and if they have similar rights - especially if they "invited" the company into their home to quote. Most general advice is only really applicable to the Consumer Credit Act and as such we are of the opinion that "Cash Buyers" do not always have the same statutory rights.

We feel this is very unfortunate especially as most companies we know will allow at least a seven day cooling off period - no matter if you are a cash buyer or a credit buyer. It sounds as though you have been unfortunate to come across one of the few who does not behave in such an "honorable" way. (We are also very pleased to note they are not listed on our site)

Your best defence is that you where mislaid by the sales representative and there may be some merit in pursuing a civil action against him. As you will appreciate - we are not lawyers and as such we would advise you to take legal advise ASAP. You should find some help at your Local Citizens Advise Bureau and it may be that Trading Standards will be interested. In recent times the Office of Fair Trading have been particularly keen to challenge companies with "unfair contract terms". We think it's quite likely that some of the terms of this company's contract are unfair and it may be that you have some additional "defence" there.

We are very disappointed to receive a question such as yours - especially as the Double Glazing industry have generally speaking done a lot to stamp out practices such as this. We do not feel you are without hope - but are sorry we cannot give you more encouraging news.

If anybody else reading this answer has any more specific advice we would be pleased to receive it.

Question submitted by M Ronson

My Daughter has just purchased a new build property adjacent to a railway line. We do not believe that the double glazing units installed by the developer comply with the specification supplied to us prior to purchase, as the noise transmission is quite high. The spec for the living room is 10-12-6 and the bedroom is deep void. What do these specs mean? And how can we establish whether these have been fitted.

This question answered by the Windows Today editorial team - 10-12-6 stands for a 10 mm pane of glass separated by a 12 mm cavity (air gap) from a 6 mm pane of glass. Most normal double-glazing uses two panes of 4mm thick glass. The thicker the glass used - the better the sound and heat insulation. A larger air gap will also improve sound insulation. At 28 mm overall thickness the above type of sealed unit is one of the largest sizes of sealed unit available.

There are electronic tools available which will measure the overall thickness of sealed units and also the thickness of glass. A specialist glass merchant or building surveyor specialising in glass and glazing would have such tools. Another way, which may not be so easy for you - is to remove the glass and measure the overall thickness of glass and glass thickness' that way. These are not easy solutions for most people - perhaps you should get your original supplier to return to site and prove that they have supplied what was specified. The specification sounds quite good to us and if used would certainly be better than "normal" double glazing.

As a last resort you could consider also installing secondary double glazing on the inside of the replacement double glazing. Because of the much larger air gap created by secondary glazing the sound insulation would be improved even more.

Question submitted by Andrew

We have a 75 year old house, with original sash windows. We'd like the benefits of pvc-u double glazing, whilst preserving the overall appearance of the house. I've seen many installations in houses like ours, and remain to be convinced by most of them. Does anybody make pvc-u double glazed sashes ? Are there any other options ? The windows need replacing, so secondary glazing doesn't seem to be sensible - it doesn't look too nice inside, either !

This question answered by the Windows Today editorial team - Sliding sash style PVC-U windows are available. One extruder with a good reputation for this type of window is REHAU. There are many fabricators and installers of the Rehau product and it should not be very difficult to find a supplier who can supply you. Many companies advertise Rehau in their adverts but if you have any problems you could contact Rehau themselves. Their web address is
They have an article on their range sliding sash windows (called the Heritage vertical sliders) at - In this particular instance PVC-U sliding sash windows were used in a conservation area. This is quite an achievement for a PVC-U product as until now PVC-U has rarely been used in conservation areas.

Question submitted by Cally 

I have recently bought some white UPVC windows to replace aluminium windows to fit myself, can you give me tips on the best way to fit these windows?

This question answered by Cavan Sullivan of Welsh Window Systems.

Note: We assume that you are fitting into either face brick or rendered finish brickwork.

You can use screw and plugs, fisher bolts or tapcon type screws to fix your window to the brickwork. All screws should be plated to stop corrosion. Generally you will need 70mm 100mm and very occasionally 125mm long screws.

The exterior window sill should be fitted first if required. Make sure that if you fit an external sill you fill across both ends where the window sits with a suitable silicone. Failure to do this is a major cause of leaks where water drops down into cavity below and very often leaks over the head of any existing windows or doors below.

The window should then be offered into place. Level and plumb the window and temporary wedge into place. On large windows use a large straight edge to make sure window is level. Once you have wedged window into position stand back and check window looks correct in the opening. You will need to do this from inside and outside.

On windows less than 1200mm there is usually no need to fix the head. Windows should be fixed every 450mm and you should always keep at least 150mm away from every corner or weld. With top openers quite often there is less than 300mm between welds and in this case you should screw in the middle of whatever gap you have. If the window looks good you can proceed to completing the fit.

When fixing screws you will need to pack between the frame and the brickwork. Typically this is done with "glass packers" and you do this in order to stop the PVCu "bending" or "deflecting" as you tighten the screws. Do not over tighten screws.

One thing to watch out for - especially on wider windows is that the transoms are level. Some times if the screws are over tightened the frame may twist a little leaving the transom out of level. If the transom is our of level then the openers will not open and close correctly.

When you are happy window is fixed okay you can proceed to fit the glass. Make sure you have the correct glazing packers. Fit two bridging packers approx 150mm away from each corner. These are packers with a gap through the centre to let any water run through. Also take care not to cover drainage slots with packers. Incorrectly fitted or wrong type of packers are the cause of many premature sealed unit breakdowns. (Please note that sealed unit manufacturers will consider you have "voided" their warranty if you have placed packers in the wrong places.) Use a centre packer on panes over approx 1800mm.

If you have snap in glazing usually any frame gasket is already fitted. If not you will have to fit yourself. (NB - put the gasket join at top of window and "nip" / partially cut away at the back on the corners - in order to turn gasket at right angles - do not cut into four pieces.)

Lift glass in carefully and square up in opening with equal amounts of gasket showing on each side. You may also have to put a glazing packer on top of bridging packer if needed to lift glass to show equal gasket top and bottom. Carefully tap in beads with a rubber hammer. Its best to try a small pane first as beads are hit in differently depending on PVCU system.

Always push glass against back gasket lifting glass slightly at same time before tapping in beads or fitting an internal wedge gasket. If your windows uses wedge gasket then this gasket is pushed in last of all after fitting beads. (Fit along bottom first but with join at top - this is "important") If your window system requires you to tap in beads then fit top and bottom first followed by the sides.

On fanlights or small panes you may have to fit smallest beads first. If you have access to a low expansion gun foam you can foam around the window and when cured you can remove packers/wedges behind screws. Note - do not remove packers/wedges if fitting doors. If you do not use a foam then leave packers in but cut back flush with frame if needed.

Finally trim with PVC trims as needed and finish with a good quality low modulus silicone sealant.

Cavan's web site is found at


Question submitted by Kal

I've got a PVCu door and would like to replace the lock, in particular just the barrel with a new one. The question is how do you replace it?

This question answered by the Windows Today editorial team - To remove existing barrel open the door. At the same level as the barrel you will find a locating screw in the side of the door sash. This screw holds the barrel in place. Remove the screw. Now place the key in the barrel and turn it either slightly to the left or right (about two o'clock position). In this position you should now be able quite easily to 'wriggle' the barrel out of the lock. You need to insert the key in the barrel as most barrels are 'off set' - i.e. they will not come out in the 'straight up' position.

If you have lost the original key - you may wish to consult a locksmith. Alternatively (and this can be 'tricky') drill the barrel out using a high-speed drill. Be aware that some companies now use special 'anti drill' barrels - so this can be quite a job. Best to have lots of spare sets of keys!

You can purchase new door barrels from most door suppliers - typical costs are 10 - 20.

Question submitted by Steve

I have recently had a 8ft x 6ft all white PVCu lean to conservatory built to the rear of my house. I intend to use it as a study. It is built on a dwarf wall concrete base. Suffering from condensation from roof supports and floor level joints. I am using fully controllable oil filled radiator to heat as main wall not sufficient for a radiator. Could you please offer some help to my problem?

This Question answered by Tina Dunlop @ Almost Impartial Guides - The good news is that your levels of condensation are likely to reduce as the "building works" dry out. It is not uncommon for conservatories to take as much as 6 - 12 months to dry out once built. During this period condensation will be particularly bad. However there is no guarantee that you will not have condensation after this period - especially if you have "only" used normal double glazing and 16 mm polycarbonate. My best suggestion is to install a dehumidifier (you can hire this) for a few weeks - this will remove a lot of the moisture. Also continue to vent the conservatory - a lot of people keep the windows closed - believing this will help - It is far better to let the air circulate. You may also find it beneficial to install "trickle vents" in your frame work - which allows you to have some ventilation with-out opening your windows. Trickle vents are available from most double glazing suppliers at 15 - 20 each. 

Question submitted by Gary

Where would I get something to keep the French doors of my conservatory open, to stop them blowing to & fro in the wind, & to stop my little boy from trapping his fingers in them?

This question answered by the Windows Today editorial team - Some suppliers will supply (or you can purchase separately) special 90 degrees restrictor stays (hinges) that are fitted to top of door. These limit the amount of opening to 90 degrees. In my opinion they are not the best solution as you may wish to open by more than 90 degrees.

A better alternative in my opinion is to fit "cabin hooks" (as often seen on ships). These are easy to obtain from hardware stores. Attach the "eye" to the French Doors by means of "self taping screws" - then attach the "hook" to the wall next to the door. With this method you can secure the door open in an open position and protect your child's hands.




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