Provide Code 4 stepped lead flashings, with stepped cavity trays at all roof / wall abutments. All lead flashings to have a minimum of 150mm upstand at abutments.
DRAINAGE – RAINWATER
Provide 100mm dia. half round, deep flow black upvc gutters, with 68mm dia. rainwater pipes discharging into new trapped gulley with rodding access, connected to 100mm diameter clay pipe laid to a minimum fall of 1 in 80, and to connect into existing system. To be approved on site with Building Inspector.
125mm H.R. mm UPVC gutters laid to fall of 1 in 300 to outlet with 68mm dia. UPVC rainwater pipes.
DRAINAGE – FOUL WATER
All drainage to be ‘supersleve’ or ‘hepsleve’ pipes laid and bedded in accordance with manufacturers’ instructions and recommendations. Inspection chambers to be ‘hepworth’ type polypropylene installed according to manufacturers’ specification. Manholes to be constructed in 225mm class ‘b’ engineering brickwork or proprietary concrete rings on 150mm thick sulphate resisting concrete base with step irons to b.s. 539 – 150mm average benching laid to falls.
Below ground 100mm dia. soil pipes laid at 1:80 minimum gradient. Soil pipes and accessories to B.S. 4514, 100mm dia. soil and vent pipes to be positioned externally with mesh covered outlet positioned 900mm above any opening light. SVP to discharge directly into inspection chamber via 100mm dia. rest bend. SVP to be encased in sound insulated duct (see internal wall spec.) where it passes through living room or bedroom if internally located. Include lead slate and saddle where SVPs pass through the roof.
Sink, Bath, Bidet & Shower = 76mm deep seal trap, 40mm dia. UPVC waste pipe @ 18 to 90mm/m fall.
WC = 50mm deep seal trap, 100mm dia. UPVC waste pipe @ 18mm/m min. fall connected directly to SVP.
Washbasin = 76mm deep seal trap, 32mm dia. UPVC waste pipe @ 20 to 120mm/m fall. Provide anti-syphonic traps & 50mm dia. UPVC waste pipes where pipe run exceed 2.0m. Where common waste pipe is used for one or more appliances it must be a minimum of 50mm diameter and connected to SVP or back inlet gully. Rodding eyes to be provided at head of all drains. All gullies and SVP’s to have rodding access. All stub stacks to have an AAV (Air Admittance Valve) fitted and rodding access.
DRAINAGE – GENERAL
All new drainage to route and connect into existing correct drainage runs in compliance with building regulations and to be approved on site with building inspector. Building contractor must verify on site that new foul drainage connects into existing foul drainage and new surface water drainage connects into existing surface water drainage. All below ground drain pipes should have minimum of 150mm cover below slab level and be encased in 100mm minimum of concrete. All drains passing under buildings to be tested and approved by building inspector and bridged over (see lintel spec.) where passing through walls. All existing drainage lines shown on drawings are assumed for guidance purposes only (designer holds no responsibility) and must be checked / verified on site by contractor prior to commencement of works / new drainage construction.