SWISH BUILDING PRODUCTS
LICHFIELD ROAD INDUSTRIAL ESTATE
STAFFS B79 7TF
Tel: 01827 317200
Fax: 01827 317201
Suppliers of: PVCu cladding fascia soffit boards PVC weatherboard plastic bargeboards PVC rainwater goods, PVCu Fascia
Swish Building Products is one of the UK’s leading manufacturers of low-maintenance cellular PVC building products, including fascia, bargeboards, internal and external cladding.
These low-maintenance building products are well accepted within the public sector, with both Local Authorities and Housing Associations, and within the private sector for domestic, commercial and new-build applications.
The Swish Roofline range offers the specifier a fully integrated fascia, soffit and bargeboard system with a wide range of components in white, foiled and coloured finishes for new build and replacement projects.
Swish cladding is a weatherproof rain screen layer that can help to improve the thermal performance of a property when installed in combination with insulation. There is a choice of Shiplap, Open V, Tee Gee and Featheredge designs available in four sizes.
Swish offers a 20 year guarantee on its white cellular PVC profiles which also carry BBA and BSI certification. The popular foiled and coloured boards carry a 10 Year Guarantee as does the Swish Rainwater system.
The Swish rainwater system is ideal for those who wish to specify quality products that have a reduced carbon footprint as it is manufactured from 84% recycled PVC material.
All Swish guttering systems and colours are Kitemarked and are offered in a range of:
- Round Gutter
- Deep Gutter
- Ogee Gutter
- Square Gutter
Since being awarded ISO 14001 in 2007 Swish has concentrated on reducing the carbon footprint of its manufacturing and distribution facilities and is now one of the most efficient and environmentally responsible plastics manufacturers in the industry. Swish has consistently reduced its CO² output, water consumption and waste generation during this period. In 2014 Swish was awarded ISO 50001 Energy Management Certification which it holds alongside Responsible Sourcing of Construction Products –BES 6001 and the Occupational Health and Safety OHSAS 18001 Certifications.
A range of Gallows and Dentils for roofline, canopies, bay and oriel windows. The dentils may be secretly fixed and the gallows brackets are load bearing and capable of offering structural support to door and window canopies.
A wide range of trims that provide a neat, clean and dry means of finishing or making good the areas around windows and doors. They eliminate the need for wet trades, thereby reducing installation times to a minimum. Many may also be used as decorative additions in roofline and cladding installations.
Window boards and trims provide a neat, clean and dry means of finishing or making good the areas around window and door reveals. They eliminate the need for wet trades, thereby reducing installation times to a minimum.
Further technical information, image galleries and product specifications are available through the Swish Building Products website or via the BPi Download Library.
Swish Building Products - Let's Look at Cladding
Let's Look at Cladding
As with other roofline materials, most problems with cladding start with rot. We live in a damp climate and timber cladding can suffer badly and need replacing if it doesn’t see regular maintenance.
Here, we’re going to look at cladding best practice. Some do’s and don’ts that will minimise the need for future repair and maintenance and ensure a good standard of workmanship for your customer.
First of all – choose the right material for the job. Softwood used to be the favourite but cellular PVC is now the best choice for external cladding. It won’t rot, it doesn’t need painting, you don’t need special tools to fit and it costs roughly the same as timber. What’s more, it will last the lifetime of the building.
Swish cladding is a foamed, cellular PVC material with an integral smooth and durable skin. It won’t warp, flake or peel, nor will it support bacterial or fungal growth.
So, if you are faced with cladding replacement because the old timber is past its best, what’s the best way to tackle the job.
1. Firstly, it’s best to remove all existing boarding to get a good look at the substrate behind. If the external cladding is in a poor state of repair, the chances are the battening behind will be too.
2. Through ventilation should be provided behind the cladding, with an unobstructed air path at the top and bottom of the clad area.
3. For white cladding, fixing battens should be good quality treated softwood and a minimum 19x38mm, although 25x38mm is better as these create the recommended 25mm ventilation gap behind the cladding. Batten fixing centres should be set at 600mm for buildings up to 2 storeys. [400mm maximum for 2 to 5 storeys].
4. For foiled cladding, battens should also be good quality treated softwood and a minimum of 50x38mm, to create a minimum 50mm airspace behind the cladding. Fixing centre should be 400mm maximum. Continuity of the ventilation path must be maintained by omitting the starter batten and by venting into the eaves or by leaving a 10mm air gap between the cladding and the soffit. Angle ventilators can be installed at the base and top of the cladding to prevent ingress of insects.
5. Where additional damp-proofing is required, say for insulated structures or in exposed locations, it is advisable to use a breather membrane behind the cladding. In timber frame construction a breather membrane is essential. Where insulation is installed, counter-battening will be necessary to maintain a ventilated air space. In case of doubt, Swish technical staff will be happy to advise.
6. Expansion gaps: As a general rule, an expansion gap of 4mm should be allowed at each board end.
7. Fixings: For all cladding profiles, 30mm, A4 stainless steel fixing pins are recommended.
8. Sealants: Where detailing requires the use of a weather seal to prevent ingress of rain, snow, etc for example at perimeter junctions and openings, Swish low modulus silicone sealant is recommended.
9. Trims: A huge range of cladding trims is available. These are designed to ensure expansion gaps are covered so that water ingress is minimised and a clean finish is achieved around edges and openings. Starter trims for the lower edge of the first plank ensure a neat, professional finish and universal channel can be used at all ends, abutments or around openings. Two-part trims make installation easier when working with short-length boards.
10. Finally: Make sure all board-ends have the correct expansion gap and are properly fixed. Check plumb and level every third row as small deviation can become visible over the clad area. Also, do not butt ends of cladding boards tight up to each other and rely on silicone as a suitable finish. It will cause distortion, the sealant will deteriorate and it will soon look a mess!
Dave Osborne is Technical Manager for Cellular PVC cladding specialists Swish Building Products. For more detailed guidance, we also recommend readers to refer to Swish Design and Specification Guide and to the Plastics Industry Code of Practice, available from The British Plastics Federation.
Swish Building Products - Roof Void Ventilation
Dave Osborne, Swish Technical Services Manager, takes a look at roof ventilation and the important part it plays in maintaining healthy building stock.
Modern homes can generate a huge amount of water vapour – baths, showers, cooking and general living all produce moisture that’s held in the air around us.
Warm air can hold much more water vapour than cold but when warm air comes into contact with cold surfaces, it cools and releases excess vapour in the form of condensation.
Ventilating the living space is relatively straightforward, either with passive methods – opening a door or window, or by using mechanical ventilation systems such as an extractor fan.
What is less straightforward is the ventilation of the roof void above. Water vapour can pass through most building materials and will permeate the roof space through plasterboard ceilings, service holes, downlight fittings and loft hatches etc.
When it reaches the roof void, the temperature difference is often at its most extreme and moisture is readily deposited on cold surfaces much the same as dew on the grass – hence the term, dew point.
Once moisture has entered the roof space, the most practical and effective way of removing it is through ventilation.
Unrestricted air movement
Building Regulations Approved Document 2 and BS 5250, Code of Practice for the Control of Condensation in Buildings both recommend ventilation to control the build-up of moisture in the roof area. At its most basic, this involves allowing air to enter the loft at the lowest point on one side of the roof and exit on the opposite side.
Clear, continuous air paths at the eaves are therefore crucial, as without the through-flow of air, the performance and condition of the materials that make up roof construction can be compromised.
The temptation to over-fill with insulation material close to the eaves in the belief that heat retention will be enhanced should also be approached with caution, as this may restrict the ventilation path leading to condensation, mould and deterioration of the structure.
The size of the air path across the roof void is determined by the style of roof construction: Mono pitch, Duo pitch or Flat.
•Duo pitch roof, greater than 15 degree pitch but less than 70 degrees, with insulation at the ceiling level = 10mm.
•Duo pitch roof, greater than 15 degrees with the ceiling following the plane of the roof = 25mm at the roofline and 5mm at the ridge.
•Mono pitch roof, greater than 15 degree pitch but less than 70 degrees with insulation at ceiling level = 10mm at the roofline and 5mm at the ridge.
•Flat roof less than 15 degree pitch with insulation at ceiling level = 25mm.
•Duo pitch roofs greater than 20 degrees pitch or greater than 10m span should have additional ventilation at the ridge to assist airflow through the roof void, equivalent to at least a 3mm wide continuous gap. Additionally, if the span is greater than 10m, the overall ventilation area should be increased to at least 0.6% of the total roof area.
•Where the duo pitch is greater than 15 degrees with the ceiling following the plane of the roof or a flat roof, less than 15 degrees pitch with insulation at ceiling level, a minimum 50mm free air path should be maintained between the top of the insulation and the underside of the roof decking. Air paths should not be obstructed.
There is one solution that allows for both adequate ventilation and good insulation. Swish Building Products recommends as best practice, the installation of eaves vent trays or roll-out eaves trays in conjunction with soffit ventilation. These are designed to sit between the rafters, above the insulation, and force the insulation away from the roof, ensuring that the flow of air is maintained.