UPVC Fascias And Soffits Installation - A How To Guide
Fascias are a structural component of your roofline so it is important to make sure they are measured and fitted properly. In this article I’m covering fascia and soffit replacement on tiled runs and flat roofs.
Installing Fascias – Measuring Fascias For A Tile Run
The first row of tiles rests on the fascia, so this measurement must be accurate. If measured incorrectly, a shallow fascia kicks out the connection between the first row and second row of tiles; a tall fascia slows the rainwater and allows water to build up into torrential downpours.
It is very easy to get this wrong and either outcome results in water getting beneath the tiles – eventually giving you rotted battens, felt deterioration and water inside your property.
So, to get the precise measurement, you need to measure between the very bottom of the tile and the underside of the soffit. If you intend to install over facia vents and bird combs remember these thicken the height and you have to adjust the fascia measurement to accommodate them.
Important Tip: Never allow vents to be load bearing at the ends of a run (such as hips and box ends) as these areas need the support more than any other area of a run.
Only allow around 150mm before a vent starts. For bird comb allowance allow an extra 5mm on the fascia replacement. If the measurement is too tight it warps how the tiles sit adjacent to cemented down tiles on either end.
Check the fascia height is consistent along the run – use the same method at each end of the run and in the centre. On some older houses, or houses where the brickwork is not level, a fascia height may creep and be considerably different in some places. If this is the case, and you are not confident about raising hips and verges to alter the bedded tiles, try to make the measurements fade into each other. If you have a difference of more than 15mm, it may be worth checking how the soffit is installed (especially if the property is around 60 – 70 years old) as this much difference is a very rare occurrence.
If you are installing fascias over 5m long you need at least one joint. I recommend staggering fascia joints from soffit joints as each joint is a potential weakness. Therefore, staggering the joints strengthens these areas considerably.
Also, avoid installing fascias any smaller than 1m as you would only have 1 solid fixing onto the studwork and it would, over a period of time, start to warp.
For example: if the overall length of a run is 9m then you can split it into a 5m length and a 4m length – whereas for a 5.5m run you would go for a 1m and a 4.5m length.
Installing Fascias – Measuring Fascias For A Flat Roof
It is far easier to correctly measure for a flat roof. Whilst the fascias here are not load bearing, there are other areas that need attention that a tiled run does not.
When installing fascias on a flat roof aim to enclose it and have a tight fit. Your ripped out run shows the exposed joists where the flat stirling board sits.
The measurement for these straight runs is from the stirling board down to the soffit (if applicable) or to the middle of the top course of bricks. This creates a tight fit overlapped by the felt at the top and with a good 25 – 40mm overlap past the brick.
Normally a flat roof fascia needs the lip of the fascia board removed to stay flush with the wall. You can make it watertight with a bead of silicone after all the guttering and cleaning has been done.
Measuring Awkward Areas
You may find you have some awkward areas to measure. These are the areas I’ve come across along with tips on how to measure them.
Valleys – not every property has these. They are areas where the roof comes to an internal 90° corner. Generally the fascia in this corner is a little bit shallower than the rest of the run. Ripping out old fascias will expose the valley board behind and some lead. Do not be tempted to move these or to vent these areas.
A valley normally stretches between 200mm and 300mm each side and is usually a different height; sometimes a difference of 20mm – 50mm. Take as many measurements as you need to until you are confident about going ahead.
Shower / Oven Ventilation – ventilation covers are normally installed in soffits and sometimes have a little play in them. This means you don’t have to worry about exact measurements. Make sure the gutter clears the area though.
Making the pipe connection fit can be tricky. Take care because if it is not installed correctly exhaust steam can pour into the roof giving you extreme condensation in the attic.
Overflow pipes – these are pipes that poke out of the fascia and are connected to tanks in the attic space. If you have installed a product (such as a combi boiler) that makes the tank redundant then it is not necessary to install the overflow pipes again. If they are still in use then you need to measure where they can be sited so they don’t interfere with the gutter. I generally use a router blade and make the holes as low as possible.
Installing Fascias – Preparing Fascia Lengths
Once you’ve completed the measurements you are ready to cut the fascia boards. A good wood saw is OK to make small cuts. Use a cordless circular saw for a longer cut.
Mark out as many of the measurements on the fascia as possible; this acts as a ‘double check’. Always bear in mind that the measurement from the underside of the tile to the soffit is an internal measurement of the fascia and not an overall height. Do not include the lip (which is normally 9mm) when marking your measurements. For example: if a fascia height from tile to soffit is 150mm then the actual overall height (including the lip) is 159 – 160mm.
Prepare one board at a time and fit one board at a time. Do not measure a 7m run and prepare a 5m and a 2m. There’s a good chance you may need a few millimetres more, or less, on the last board of the run.
Take it slowly and always measure again if in doubt rather than getting it wrong. Achieving a snug job takes a lot of concentration. Get it right first time and you avoid going up the ladder again to redo a rushed job. It is worth taking your time because in some places on a roofline 5mm too short is an open invitation allowing pests inside.
Always wear safety goggles when ripping plastic boards down as the shavings literally cover you in fine dust that scratches your eyes. Take it slowly and finish off by marking a rough line for a nail height on the protective film of the fascia.
Make sure the nail position is in the centre of the overall height of the board. Consider using 2 nail lines for fascias any higher than 200mm.
Similar to soffit installation, fascia board installation – especially the longer lengths – is normally a two person job as a single pair of hands cannot be at both ends of a 5m length of board at the same time. Keep the gap between the joints as small as possible whilst allowing expansion gaps of around 5mm.
Use 65mm nails and do not leave any play between the back of the fascia and the studwork behind. You need a nice tight fix that is load bearing for the tiles to rest on.
Once the fascias are fixed in place, use a level to check for any sloping areas.
At this point, give the fascias a quick clean and any joiners that need to be done can be glued into place. Consider screwing the joints together for extra support in case the joint has fallen between the studwork.
Something To Think About…
Fitting fascia lengths on your own can be very dangerous, especially when trying to hold the fascia at the same time as driving a nail into the roof truss / studwork behind it. If you don’t have anyone who can give you a hand, or if you have any concerns about working at heights, then I urge you to seriously consider getting a professional in to replace the roofline for you.
A roofline specialist, such as Anglia Roofline, have the right experience to remove the old roofline and fit your new one. . . including installing soffits, installing fascias, bargeboards etc.
Fascia Board Replacement Cost
If you are in the Norfolk area, why not ask for a free, no obligation quote? I will visit you for just 30 minutes during which time I inspect the current state of your roofline. I’ll give you an honest report on what is needed and what it will cost to fit a quality uPVC roofline guaranteed to last 20 years. Plus, if you can be flexible on when the work is carried out, you could save up to £825 off your quote.
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Owner & Director | Anglia Roofline Company Ltd