 Cast Iron Installation
Generally
BS 8000 Workmanship on building sites, Part 13 Code of Practice for above ground drainage and sanitary
appliances: 1989 is relevant in general terms. Imperial Dimensions
All products in the Apex Heritage Cast Iron range are manufactured to conform with original imperial
dimensions which assist where an existing installation is being required or being replaced. Fixing holes can be reused, thereby saving not only time but the building from unsightly repair. The original building fabric is also left undamaged, an important consideration when dealing with historic buildings. Gutter Falls
Where possible a fall of 1:600 to 1:350 (maximum) should be allowed for. However, gutters can be laid level if this is not possible. In replacement work falls up to 1:254 may occur, and are permissable on small buildings. Gutter Fixing
Outlets and rainwater heads should be positioned first, followed by the interlinking gutter section. For slated roofs, the gutter may be placed with the centre line under the drip edge, but on pantile roofs the gutter should be set slightly further out. Gutters should be supported at 900mm approximate centres either on brackets or, for ogee, moulded and box types, by direct screw fixing through the back of the gutter using 30mm x 16 gauge zinc gutter screws. Additional brackets or fixings should be provided at angles and outlets to prevent the risk of sagging under snow load. When fixing through the back of the gutter the screws should be tensioned gently and evenly to avoid damaging the gutter. Gutter joints are made watertight with a suitable high quality sealant. Sections of gutter are bolted together with a minimum of 3 No. galvanised gutter bolts and nuts M6 x 20 or 25mm depending on gutter profile. Where the gutter is to be direct fixed to the fascia a gutter screw is used instead of the nut and bolt at the back. It is recommended that the nut and bolt in the sole of the gutter be tightened first. The other holes can
then be drilled using an electric drill. The screws into the fascia should not be over tightened. It is no longer common practice to overlap the collar and spigot joints in the direction of flow. Downpipe Fixing
Rainwater pipes are fixed back to the wall at 1.830m (6ft) approximate centres through ears integral with the pipe, or via separate earbelt or holderbats. It is recommended that the fixing should penetrate at least 50mm into the wall. Screws or pipe nails should be galvanised. Pipe nails are available 100mm long. Preformed fixing holes through the ears are approximately 8mm diameter. Screws should be round or dome headed galvanised, using 18mm to 25mm diameter washers. Bobbins can be used to pack out the rainwater pipe fixing to give a 32mm maintenance gap for pipes up to 75mm (3”) diameter, and 38mm for 100mm (4”) pipes. Rainwater heads should be fixed back to the wall using galvanised screws and washers through the preformed holes. Proprietary fixings are also available from manufacturers such as Rawlplug, Hilti and Fischer Fixings. Downpipe Jointing Generally the joints between sections of rainwater pipe are not completely sealed. On Apex Heritage Cast Iron they are simply wedged with several lead slips 25mm wide to prevent any lateral movement. These slips should be knocked down into the 3mm—4mm gap between the outer face of the pipe and inside face of the collar, so that they are no longer visible. However where pipes are of small capacity which cannot be increased they should be both wedged and sealed with high quality sealant against a backing strip. Model SpecificationGutters
Alumasc Apex Heritage Cast Iron gutters and fixings in accordance with British Standard as appropriate
size…..profile……, Ordering reference…….Outlet size……shape……Gutters to be fixed at 900mm approximate centres, fixings with…….type brackets/direct screwed* to fascia. All manufactured by Alumasc Exterior Building Products Ltd, White House Works, Bold Road, Sutton, St Helens, Merseyside WA9 4JG. Installation
Gutters to be laid to a…fall generally in accordance with BS 8000: Part 13.* Gutters to be laid flat with no fall.* Gutter joints to be sealed with….sealant and bolted with M6x……mm gutter bolts and nuts. Gutters and fixings to be site primed, undercoated and painted with one finish coat before installation with final finish coat after. Downpipe
Alumasc Apex Heritage Cast Iron downpipes and fittings in accordance with British Standard as appropriate. Pipes size….shape….pipes without ears/with ears: Ordering reference…..pipes to be fixed with…at…..centres through ears/earbelts/holderbats:* Ordering reference……Bobbins…..thick to be used to space the pipes off the wall. Rainwater Heads Ordering reference….flat/corner type: size….. Outlet size….shape….Rainwater heads to be fixed with…..
Additional enrichments: Ordering reference……. All manufactured by Alumasc Exterior Building Products Ltd, White House Works, Bold Road, Sutton, St Helens,
Merseyside WA9 4JG. Installation
Generally to be in accordance with BS 8000: Part 13. Pipes to be left unsealed but wedged with lead slips against movement.* Pipes to be sealed with…..sealant against a …..backing strip.* Pipes and pipe fixings to be site primed, undercoated and painted with one finish coat before installation with the final coat after. Rainwater heads, including the inside, to be site primed, undercoated and painted with one finish coat before installation, with the final finish coat after. The Alumasc Rainwater Drainage Design Service Alumasc Technical Services can calculate the most appropriate system of gutters and downpipes for all of the rainwater systems that are offered. Using dedicated design software in conjunction with the requirements of BS EN 12056:2000: Gravity drainage systems inside buildings — Part 3 calculation of the most efficient drainage set up takes into consideration the following criteria: - Catchment area
- Local rainfall intensity
- Building life and safety factor
- Size and flow rate of gutters
- Frequency and size of outlets and downpipes
The gutter flow software, used by Alumasc automatically checks the capacity of downpipes used and suggests the minimum size to which down pipes can be sized. 
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Installation Guide - Cast Iron
