Used to fix your PVCu windows in place, fixings and fasteners are an important part of the process of installing PVCu windows. There are many different types hopefully this blog entry will help you to choose the right one for the job at hand.
- Wood Screws
- Fischer bolts
- Concrete screws
- Bay pole screws
Each of the window fixings and fastenings above have a suitable use and situation to be used in.
Wood screws can come in many different sizes and types – for installing windows twin threaded zinc coated is what you are looking for. The sizes you will need can range from 4mm or 5mm in diameter and 40mm to 90mm in length. As the name suggests they are for fixing into
Wood screws are often used to fix PVCu windows to their sills – it is important to pre-drill the frame then drive the screw directly into the sill until it pulls tight – it is a good idea to countersink to avoid the glass fouling on the screw head when being installed later. I would use wood screws for fixing any additional wood supports to wooden lintels. As for actually fixing windows they are not ideal and make for a fiddly and time-consuming installation.
Self Tapping Screws
Not a screw used to fix windows but to fix things to windows. Friction hinges are often held on Self tapping screws, furniture on sash windows – lifts, bow handles, fitch fasteners – letter boxes and security chains. As well items you can see they can also hold fixing straps to the window.
One of the great things about self-tapping screws is that you do not need to pre-drill. Self-tapping screws are most effective in PVC or metal. In wood they can strip out easily and do not hold very well.
If you are using them to fix into
Fischer bolts/frame fixings
Fischer is actually a trade name for a fixing like Hoover for a vacuum cleaner. Frame fixings come in several different designs but all have the same principle. A plastic sleeve that expands when the screw inside is tightened and pulls a plastic bung up the sleeve making it expand and grip the material it has been inserted into. There are many different sizes – for window fixing I would suggest at least 8mm diameter – thinner 4 and 6mm are available but not really up to the job. The most common lengths required 100mm, 120mm,150mm and 180mm depending on what you are fixing into and through.
To use an 8mm frame fixing you need to drill an 8mm hole – this will pass through the frame and into the wall – you will need two drill bits – one for the frame like an HSS and one for the wall masonry or SDS bit. You then insert the fixing into the hole until the head is snug against the frame – you may need to use a hammer to tap it home. Once in place, the frame will need to packed either side of the frame fixing to prevent bowing or distortion of the frame when done up with a large pozi drive. These fixings are best used in brick and work well in Aircrete blocks. However, they can make window installation tricky as they can move around when tightened. If a mistake is made or they do not grip and fix they can be difficult to remove – the easiest way is with a claw hammer but it will ruin the fixing.
Rarely used for window installation anchor bolts are very heavy duty. More commonly found in commercial applications where wind loading maybe a factor. You may find they need to be used on new build projects for fixing very large bi-folding doors. They are good for securing hooks for window cleaners or fire escapes – but please ensure they are fit for purpose.
Anchor bolts work in a very similar way to frame fixings expanding when tightening. They may have bolt head, flush Allen key head or tore drive. All are virtually impossible to get out once installed.
The best screw you can use for almost everything. When discovered almost 15 years ago they were life-changing – for window installers anyway. Concrete screws will fix virtually anything. The sizes I carry for window fixing 60mm, 80mm, 100mm, 120mm, 150mm and 180mm using 120mm mostly. Most use a Torx 30 bit drive them in – usually found in the box. To fix with the concrete screw you will need to pre drill in both the frame and whatever you are fixing into – wood/concrete/brick – the hole needs to be 1-1.5mm smaller than the fixing i.e. 7.5 fixing needs a 6-6.5mm hole. If you are fixing into something soft like wood or Aircrete go for a smaller hole but if its hard cast concrete (a lintel), steel or rock use a bigger hole. You won’t need to the pack the frame as the fixing bites into both the frame and wall holding firm – a big advantage for time and when using foam. In Aircrete they can pull out easily – so be careful if they need adjusting.
Concrete fixings come with either a countersink head or pan head. The self-cutting heads rarely work well and you will need to countersink before putting in the concrete screw (extra work) – We recommend using the pan head as it fits snugly against the frame and looks good with less work. You can buy little plastic caps for the countersunk fixings – but they will fall off and a neatly installed bolt looks better. Used for fixing almost everything concrete screws replace plastic frame fixings and work well in place of wood screws for strength and adjustability.
Rawl plugs seem like something from yesteryear – in window fitting they do not really have a place but they should be in your toolbox. Fixing into plaster they really are the best thing. You may also want to use them if you are fixing straps into bricks or plaster.
Working in a similar way to the frame fixings you drill a hole for the size of the plug/screw push it into the hole and when the screw is tightened the plug expands to grip the hole. These should be used for anything you are fixing to a wall – radiator brackets, large picture hooks, curtain rails,
Bay pole screws
An extra large self-tapping screw with a pan head. These screws are great. Best uses are fixing bay poles! As they sail through the PVC and cut easily into the
There are a few different types of straps from widgets, lugs, cleats, brackets etc. They all do the same thing. Straps can be designed to clip onto the window – most will be screwed on. Generally, window straps are awkward to use – but for new build projects, they are ace. When the reveals are yet to be plastered the straps can be put on the window in moments – then packed and leveled all round and simply screw the straps to a wall using Rawl plugs or concrete fixings. Job done. But with replacement windows, it’s rare you will want to disturb the reveals.
Where to find your fixings and fasteners
These are the easiest places to find fixings and fasteners for PVCu windows
DIY, trade and public suppliers
Trade only suppliers
Buy PVCu Sash windows any size from £299 www.windowsdelivered.co.uk