Suntuf Installation Guide and Tips
Installation of Suntuf is easy when you plan the job right!
Just keep our top installation tips in mind before you start to install your new Suntuf product.
Fall, pitch or slope?
Firstly, fall. A five degree fall is recommended as minimum for ensuring the roof is water tight and getting water and debris off the sheet. All polycarbonate sheets are transparent (you can see through them) or translucent (light comes through them but you can’t see through them clearly). This means that you will be able to see, to some degree, what is on top of them. Leaves, dirt, dust, bird droppings, etc. The better the fall on your roof the easier it will be for these things to fall off or wash off. The fall will also be important for dispersing water. A shallow fall can lead to leaks. Most manufactures recommend a minimum of 5 degrees. This means for every metre the sheet runs horizontally it should drop about 87 mm.
Spans – Where you will need your purlins
All profiled polycarbonate sheets require purlins or battens for fixing. These structural lengths of timber or metal run perpendicular to the fall of the sheet – see the below image for a visual explanation. Different profiles have different spanning capabilities. The below spans are given for a standard N3 wind rating, if you are in a high wind area you may require additional fixings and structure – call us to discuss.
Corrugated 800 mm End Spans and 1000 mm Mid Spans
Greca 900 mm End Spans and 1200 mm Mid Spans
Trimdek 900 mm End Spans and 1200 mm Mid Spans
Suntuf polycarbonate sheets can be cold curved. The shape of the sheet (the profile) will determine how tightly it can curve. If you want to determine if a sheet can cold curve to to suit your structure you will need to know the following information:
The chord: the horizontal distance from one side of the roof to the other.
The height: the vertical distance from the imaginary horizontal chord line to the top of the apex.
See the below diagram.
We can cut sheets to length for you free of charge. Otherwise, sheets can be cut using a fine tooth circular saw, a jigsaw, or even with a good pair of scissors. When using power tools you will need to clamp the sheet as close to the end as possible to stop vibration. Remember to allow for some overhang to ensure that water from the sheet will fall into the gutter and not onto your structure.
All materials expand and contract when they heat up and cool down, and polycarbonates move more than most roofing materials. This means that it is important to allow the sheet room to move a little after it has been installed. This is easily done by following a few rules.
Firstly, drill an over-sized hole in the sheet for the screw fixing. Both Clearfix and OneShot branded screws have cutters embedded on the screw to save you time in completing this step – they cut the hole when you put the screw in.
Secondly, by allowing a small gap between the ends of sheets and where they might come up against another object – like a wall fascia. This isn’t as important on the barge sides as the majority of the expansion will occur along the length of the sheet.
As a rule – they are not recommended. Silicons can act as an adhesive which can stop the sheet from moving (see above). Some silicons can also affect the chemicals in the sheet which protect it from UV radiation. If you can’t avoid it use a neutral cure or non-acidic silicon sparingly. Be sure not to put it along the length of the sheet where you will see the most expansions and contraction.
Purlin tape can be used to stop creaking of the sheet with expansion and contraction. As the name suggests it is applied to the purlin prior to installing the sheet, and acts as buffer. It is particularly useful with painted purlins, where in hot weather the paint can become tacky and cause the sheet to stick and make more noise as it expands and contracts.
Flashings are used to seal the edges of the sheet.. There are a few different types that are common. Ridge capping is used to flash a gable at the peak of the roof. Barge Flashing is used on the sides of the structure to cover the edges of the sheet and sometimes protect the timber structure underneath. And Apron Flashing is used to seal between a vertical wall or fascia and the roof itself. You can get a number of these flashings in polycarbonate or have them manufactured in metal.
Suntuf Flat Barge Flashing
Suntuf Flat Ridge Capping
Suntuf Profiled Ridge Capping
Suntuf Profiled Apron Flashing
Infills can be used between the sheet and any flashings or structure for weatherproofing. Infills are available in the standard roofing profiles: Corrugated, Greca or Trimdek (5-rib). An infill may be used between the the sheet and the Apron flashing on the top edge of the roof, or between the purlin and the sheet at the gutter end of the sheet to weather seal.
Back channels are normally used when the top end of the sheet is being installed directly underneath a gutter. A metal channel C- section is combined with foam to seal the end of the sheet in these circumstances.
We supply 2 brands of screws; Clearfix or Oneshot.
One Shot screws are available in either a timber T17 or a metal Tek. When screwing into hardwood or larger gauge metals they are the screw of choice. They come with a cutter to pre-cut a 10 mm expansion hole into the polycarbonate sheet, and a soft rubber washer to seal the large hole.
The Clearfix screw is a dual purpose head – suitable for both timber and metal installations. They also come with a cutter and washer to suit polycarbonate.
Store Suntuf on a flat surface away from direct light and moisture.
Warm soapy water, with a soft sponge. Be careful not to scratch the sheet. Rinse well. Don’t use other chemicals.
Installing the Polycarbonate
The standard installation guide covers the actual fixing of the sheets well. Make sure you read it. Find it here… Suntuf Installation Guide.
Allow for the sheet to overhang the lower purlin by 50 mm.
Sheets will arrive with labels showing ‘This side up’ and it is very important to install the sheets in the correct orientation. A UV layer on the polycarbonate, protect the sheet from premature breakdown. Put it up the wrong way and you will experience decreased life for your polycarbonate.
When screwing the sheets keep the screw straight to ensure weather seal of washer. Don’t over-tighten the screws. If you’re not using the branded screw mentioned above, be sure to pre-drill a 10 mm holes in sheet.
Install the first sheet screwing along the ‘lower (gutter) purlin’ from the outside (Barge side) towards the middle of the structure. Screw every other corrugation along the bottom purlin. Install the sheets without stress – that is; don’t pull, tension or twist the sheets.
Next move up to the next purlin screwing across the sheet in the same direction. Place screws as per the below diagram and continue this for all the ‘internal purlins’ or ‘mid purlins’.
Finally, Screw along the top ‘upper purlin’ placing a screw every second corrugation.
Move along to the next sheet. Use one corrugation side lap, ensuring the lap is against the primary direction of wind/rain. Finish the job by installing any required flashings. Don’t forget to remove any stickers or tapes from the sheet.
Thanks for looking at our Suntuf Installation Guide and happy installing!