SLE Cladding Limited

Introduction

Product Range

DR - Double reinforced Sheets. Available in translucent and Opaque as a direct replacement for asbestos-cement profiles which are no longer manufactured.

To enhance strength and impact resistance, these sheets incorporate additional woven reinforcement. This extra reinforcement provides a strong composite with sufficient "built-in" flexibility to enable the sheets to be more easily fixed into an existing rigid asbestos-cement roof.

Profiles
To match six asbestos-cement profiles as listed in Table 1.

Length
There are three standard lengths available in most profiles - see Table 1.

Weight
Weights are shown in Table 1 to provide the impact strength required. Heavier weights can be manufactured to meet specific structural wind loadings.

DR sheets are primary designed for completing repairs to old asbestos-cement sheeted roofs. They can be used as a direct replacement or laid over existing damaged sheets.

   In either case, this involves removing fixings and fitting the DR below the asbestos-cement sheets at the head laps and the underlapping side laps.

   As this involves a certain amount of pushing and pulling, the additional strength of DR reduces the possibility of falling through damaged or broken asbestos cement sheet whilst remedial work is in hand or if anyone accidentally steps on the sheets after the work has been completed.

   All asbestos-cement roofs must be considered fragile and crawling boards should be used at all times.

Colours
Cement Grey

Fire Grade
To meet Building Regulations requirements, sheets are manufactured in two grades, which have been tested under BS.476 "Fire Tests": Part 3 and 7, and have been classified as follows:

Grade 104 - Designated AA Rated Class1
Grade 300 - Designated AB Rated Class3

Performance
All sheets are treated to the weather face with ORTHOFLEX gelcoat to ensure a surface life of at least 30 years.

TABLE 1.
Sheet Length mm	1550	1850	1975	2150	3050	Weight kg/m2
Cape Fort			*		*	*
Cape Monad			*		*	*
Double Six				*	*	*
Double Six M				*		*
Major Tile			*		*	*
Trafford Tile	*	*	*			*

Siteworks

Structural
The DR sheets in the profiles listed in table 1. have been tested in accordance with HSE Drop Test (Health and Safety Executive, Specialist Inspectors' Report No. 30 "Fragile and Non-Fragile Roofing Materials").

To simulate a human body falling against a flexible material, this test uses a 300mm diameter bag containing 45 kg of dry sand, which is dropped 1.2m on to the centre of an assembled test area. Sheets are now required to retain the bag after 2 drops.

On tests completed using a safety factor of 2 by increasing the drop distance to 2.4m, DR sheets secured to purlins recommended by asbestos-cement sheet manufacturers, successfully retained the test weight from falling through the sheet. After 2 drops DR had at least twice the impact strength of standard GRP translucent sheeting.

Applications

Fire Building Regulations
On a single skin application, where the underside of the sheet would be exposed within a building , specify Grade 104. On double skin applications, where the underside of the sheet would be protected by linings, specify Grade 300.

Structural
On normal exposed buildings, not exceeding 10m high with normal permeability's, fix sheets in every corrugation and secure sidelaps at centres not exceeding 450mm. Where sheets are not supported on the underside by asbestos cement sheets, rigid shaped supports are required to be located between the underside of the sheet and the supporting member to take the pressures required by the sealing washer without distorting the sheet.

Structural (continued)

On buildings exceeding a height of 10m, or where they are sited in exposed locations, or where high permeabilities are likely, or in zones of high local loadings adjacent to verges, check with the manufacturer's Technical Services Department foe recommendations.

Storage
Sheets are generally supplied loose. Store on clean level battens at centres not exceeding 1.5m. Stacks should not exceed 1m and must not overhang at ends.

Secure and protect from wind and mechanical damage. When stored in open protect with opaque waterproof covers.

Cutting and Drilling.
Cut sheets with a hacksaw with 6/8 teeth per centimetre. Best results are obtained if the saw is held at a shallow oblique angle. When cutting with power tools use 40/60 grit diamond blade operating at medium speed.

Labour Safety

Do NOT walk on sheets, ALWAYS use crawling boards. Attention is drawn to the Health and Safety Executive Guidance Notes HS (G) 33 " Safety in Roofwork" published by HMSO. Particular attention is drawn to paragraphs 29-35 inclusive detailing safety precautions which must be put into practice.

Although DR sheets are designed to withstand impact from a falling body, they will deflect under local point loadings. To prevent any deflections damaging the sheets or sealants, crawling boards MUST always be used when fixing and carrying out maintenance work.

Above: Refurbishment of garage block with "DR" Doublesix

SLE Cladding Notes.

Ref. Obsolete Profiles

There can be a problem with really obsolete profiles, insomuch as the manufacturers require orders totalling a minimum quantity of 50 linear metres before they will commence a production run of any one profile. This quantity of orders may take a few days, weeks, months or even years to assemble if it is a really old one or has been an unpopular profile. Glass Reinforced Plastic is expensive and fifty lin. metres is far too much to purchase if only say 2 sheets are required.

The standard sheet colour is cement grey and the surface of the sheet is very smooth. Whilst all colours and surfaces degrade over time, it will be some years before the sheet surface is capable of retaining paint.