Edge trims, outlets and drainage across Cheshire

Guide price

£110–£330

Repair price

Confirmed once the leak or damage is found

Condition survey report

£140–£290

Coverage

England, Wales, Scotland, NI

How much does a new roof edge or outlet cost in Cheshire?

Guide prices including VAT at North West rates. We confirm the price once we've traced the leak or seen the damage.

Which flat roofs are common in Cheshire?

Flat roofs in Cheshire sit on terraced streets with flat-roofed rear kitchens and bathrooms, newer estates where the first extension roofs are now being replaced and shops with flat-roofed rear stores below flats. The North West is one of England's wetter regions, averaging roughly 1,290 mm of rain a year, so falls, outlets and well-detailed upstands matter more than the membrane colour. Approximate 1991–2020 regional averages based on Met Office data.

Building regulations in England

Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In Cheshire the application goes to Warrington Borough Council, Cheshire West and Chester Council, Cheshire East Council and 1 other council. More on the rules.

Do flat roofs need overflows?

Roofs that drain to internal outlets or behind parapets should normally have an overflow, so that if an outlet blocks, water spills somewhere visible instead of rising over the upstands and into the building.

An overflow is usually a spout or weir set through the parapet or kerb at a level below the top of the upstands. When water runs from it, that is a sign the main outlet is blocked or overloaded. On a simple roof that drains over a drip trim into an external gutter, the open edge itself does the same job.

We look at where the water goes in heavy rain, how many outlets the roof has for its size, and whether the outlets, hoppers and downpipes are clear and properly connected. Leaf guards on outlets help on roofs near trees, as long as they are cleared regularly.

Why does water sit on my flat roof?

Water sits on a flat roof because it can't drain off fast enough: the falls are too shallow, part of the roof slopes the wrong way, the deck has sagged between joists, or an outlet is blocked or set too high.

Current guidance on flat roof design (BS 6229) means most roofs need to achieve a finished fall of at least 1:80, and roofs are commonly designed with a steeper fall, such as 1:60, so that building tolerances and deck deflection still leave enough slope. Many older roofs were built with less, or have settled over time.

A small amount of water that clears within a day or two of rain is often tolerable. Deeper ponding that lingers adds weight, holds dirt and debris, can shorten the life of some coverings and turns any small defect into a leak. A patch won't fix it, because the problem is the shape of the roof. The fix is to correct the falls, either with firring pieces under a new deck or with tapered insulation in a warm roof, or to add or lower outlets so water has somewhere to go. Our ponding water guide explains this in more detail.

Which towns in Cheshire do we cover?

• Warrington
• Chester
• Crewe
• Ellesmere Port
• Widnes
• Macclesfield
• Northwich
• Great Sankey
• Winsford
• Congleton
• Wilmslow
• Sandbach
• Nantwich
• Neston

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