Installing Cast Iron Rainwater Goods
Technical Support
With our experience, Stoneware Studios can provide technical consultancy, on site help, or general information on Cast Iron Rainwater systems. Please call our office 024 -90117.
Jointing Methods for Cast Iron Rainwater Pipes
Vertical rainwater pipes are not normally sealed. Only seal joints in a horizontal position e.g. 90 degree branch arm or bend.
It is recommended that three small wedges made from sheet lead off-cuts are used to centralise pipe and prevent wind rattle.
Fixing methods for Cast Iron Rainwater Pipes
The traditional fixing for eared cast iron rainwater pipes is by using large headed pipe nails, available in 75 and 100mm lengths. These are secured in wooden plugs fitted in the brickwork/masonry background.
Alternatively non-corrosive coach screws or other proprietary fixings may be used. When fixing on an uneven surface such as flint walls or soft and crumbling substrates, the recommended method is to secure fixings by means of epoxy resin in pre-drilled holes.
Fixing of uneared pipes can be by drive in spike (holdfast), build in holderbat, earband or screw to wall bracket, all available from stock.
Jointing Methods for Cast Iron Rainwater Gutters
The most popular way of jointing cast iron gutters is by using a low modulus, silicone or polymer sealant or specialist, rubberized bitumen gutter mastic.
The sealant should be spread evenly within the gutter socket applying additional sealant around the jointing hole before placing the gutter spigot into the socket and compressing both parts using M6 X 25mm corrosion resistant mushroom head bolts, ensuring the mushroom bolt head is on the inside of the gutter.
The washer and nut should be lightly tightened from underside of gutter to allow excess sealant to be removed. Do not over tighten as this could result in gutter damage.
If installing Half Round or Beaded Half Round cast iron rainwater gutters our new Gutter Jointing Kit (product code HRGJK) can be used as an alternative to the traditional method.
Each kit contains 10EPDM rubber seals plus M6 x 25mm zinc plated bolts, nuts and washers suitable for 100,115,125, and 150mm gutter sizes.
The method offers the benefit of a quick and efficient joint that can be made even in damp conditions where mastics and sealants would be unsuitable.
Note: If gutters have been cut, immediately remove any loose filings to ensure there is no discoloration/rust marks on the paint surface. Also check that cut ends, bolts, nuts and any slight installation damage is made good with the appropriate primer/paint.
Fixing Method for Cast Iron Gutters
While it is common practice to fit gutters in fascia brackets, some gutter profiles may be fixed direct to the fascia if required. These include OG and moulded patterns which have three pre-drilled holes per 1.8m (6 ft) length along the top back edge. Fixing screws should be 16g x 30mm mushroom head zinc plated (available from stock).
Where building designs incorporate no fascia board, other types of bracket will be required; the most popular being side fixing rafter, top fixing rafter and rise and fall brackets with build in spike. These are all readily available in galvanized/zinc plated steel and other designs and obtainable to suit you specific requirements.
Jointing methods for Cast Iron Soil Pipes Traditionally joints are made with molten lead and untarred gaskin (yarn) both of which are available from our stock.
The bottom two thirds of the joint is caulked with the gaskin and the molten lead in then poured into the top of the joint and as it solidifies is caulked firmly in place.
Note: when using molten lead, prescribed safety guidelines should be followed to avoid personal injury or damage to property.
Alternative methods include using lead wool and gaskin or Fosroc PC4 AF cold caulking compound (available from stock).
Fixing Methods for Cast Iron Soil PipesA typical fixing for eared soil pipe is 100mm large head pipe nail, coach screws or other proprietary fixing.
Fixing of uneared soil popes is by a drive in spike. Alternatively holderbats or ear bands may be used for a more decorative effect, all are available from stock.
General Notes on Installation
Health and Safety
Safety should be the first consideration when working on any building, especially at height. As with any drainage system our cast iron popes and gutters must be fixed to sound material. It is essential that whatever surface holds the drainage system will also support the possible build up of snow and ice.
We recommend you follow the guidelines provided for safety as outlined by the HSE for work on construction sites.
Installation StandardsIn the interests of performance and safety we recommend that all installation work adheres to BS8000 1989 Workmanship on Building Sites part 13 Code of Practice for above ground drainage and sanitary appliances.
General Maintenance of Cast Iron Pipes and Gutters
HF Premier and HF premier Extra cast iron rainwater and HF Premier Traditional cast iron soil systems require minimal maintenance, but should be inspected annually. Gutters should be cleared out, particularly if the building is situated near trees where leaves and debris could cause a blockage. All soil and rainwater pipes and gutters should be inspected for paint deterioration.
Painting Cast IronHF Premier Rainwater products are coated with a rust inhibiting, grey, zinc phosphate primer. HF Premier Extra products are supplied fully coated with a zinc phosphate based paint developed specifically for iron substrates and exhibiting excellent anti-corrosion and weather resistant properties. Available as standard in a black satin finish. (Note – other colours in the BS and RAL colour range are available – please check on availability and price.)
HF Premier Soil products are delivered with a black, bituminous based paint.
It is important when painting cast iron to ensure that all surfaces are completely covered.
Cast Iron Gutter and Pipe SizingWhen sizing any roof area for drainage purposes please refer to “Drainage of Roofs and Paved Areas” BS6397 1983 or the Institute of Plumbing Handbook. Alternatively contact us –024-90117– and we will be happy to calculate and advise you accordingly.
Cutting Cast Iron PipesThere are three types of cutting tool;
- Powered disc cutter (the quickest and most popular)
- Tungsten tipped hacksaw
- Pipe wheel cutter