excl. VAT inc. VAT

The application determines manhole cover sizes and load classifications. You must measure the area to ensure a precise fit whether you’re installing a new manhole cover or replacing an old one. Regardless of the load class, if your manhole cover doesn’t fit precisely, you risk compromising the structural integrity and it could fail.

How do you measure manhole cover sizes?

The internal dimensions of the hole, not the manhole cover itself, must be measured in order for the cover to fit snugly over the hole it is concealing. Since millimetres are the manufacturers’ standard measurement unit, it must be done in millimetres for precision. Once you have this measurement, you should explore our selection of manhole covers, just use table below to determine which product is appropriate for your job, or call our helpdesk at 0161 235 1214 to get assistance.

Manhole Cover Sizes

Manhole coverings are available in square and rectangular sizes ranging from 300 x 300 mm to 1200 x 1200 mm. We also offer circular manhole covers with 450mm and 600mm dimensions.

Ductile iron manhole cover weight classes.

The same weight class system that applies to channel drains also applies to ductile iron manhole covers.

ClassMax. weight load (tonnes)Users
A151.5For pedestrian areas including gardens, patios, and driveways, very light duty.
B12512.5Domestic driveway thresholds for family cars, vans and 4x4s
C25025Roads with little traffic and small private parking areas.
D40040Highways, main roads, and heavily travelled sites such public parking lots.
E60060Loading bays, industrial parks, and freight handling yards.
F90090Extremely heavy-duty applications including docks and airports.

Types of manhole covers

Other than manhole covers sizes and load classes, there are a few types of manhole covers to choose from.

Ductile Iron

Over a D400 class, ductile iron manhole covers are sturdy, resilient, heavy-duty covers that are frequently utilised. Cast iron, commonly known as ductile iron, is utilised because of its high strength. This material then lends itself to installation at docks, airports, and other high-use industrial sectors with a lengthy lifespan.

Ductile Iron Manhole cover


Recessed manhole covers are covers with a cut out in the tray that allows for the installation of brick pavement, cement, and screed. In pedestrianised areas where aesthetics are important, this makes it possible for the recessed manhole cover to fit in with its surroundings. In hospitals, workshops, and domestic gardens where homeowners don’t want an unsightly but required manhole cover jutting out, it’s also a viable alternative for internal manhole covers.

Recessed Manhole Cover

Solid top

Manhole covers with a solid top are intended to stand out in the floor. These are generally put in places where having a manhole cover visible would be better for safety and routine maintenance than having one hidden. A visible silver manhole cover with an anti-slip surface is a common example of a solid top. In some cases, depending on where they are situated, they might also be raised. They are simple to distinguish because of the contrast between the solid top manhole covers and the solid floors.

Solid Top Manhole Cover

Ducting coils We provide a wide variety of cable and pipe ducting at PolyDrainage, so whether you need ducting pipe lengths, tracer wire, or even ducting access boxes, we can help. Our helpful crew is always accessible to answer any queries, and we have items that are suitable for electrical, gas, water, fibre optic, and even traffic and street light ducting.

Our ducting coils are stocked in 63mm & 110mm diameters. 

Below is a breakdown of the ducting coils available at PolyDrainage, and what they can be used for. 

Orange Ducting

Used to protect cables streetlights and traffic signals. 

Blue Ducting

Used to protect Water service pipes. 

Green Ducting

Used to protect any cables/ wires linked to CCTV. 

Yellow Ducting

Used to protect and cover any gas lines. 

Black Ducting

Used to protect and cover any cables linked to electricity.

To shop our range of ducting coils and accessories, click here.

If you would like to receive any extra information surrounding our ducting coils, you can contact us on or alternatively send us an email at sales@polydrainage.co.uk

Drainage gullies by definition is a drainage fitting with an open top, a definite base and outlet with one or more sides. Gullies can be used to connect wastewater outlets or stormwater/rainwater outlets to suitable drains, depending on the type. Drainage gullies can also be used to prevent drain blockages, as they let the wastewater drain, preventing any rodents or bad smelling gasses from escaping.

Varieties of drainage gullies explained…

Here at PolyDrainage we provide 3 main types of gullies. We have P Trap gullies, Bottle gullies and Road Drainage gullies.

Drainage Road gully gratings

Bottle gullies come with a grid already attached, which matched the trap. However, if you have a road drainage gully you will require a separate grating. Our gully gratings are made from composite or ductile iron and are accessed via being hinged down or being able to be completely removable. 

Our gratings are into categories based on their load class. We have load classes A-F with each class referring to a different intended traffic level and weight. 

Below shows a breakdown of the grating load classes:

To put the load classes into perspective the average patio drainage fitting can use anything from load class A15 upwards, however a carriageway (road) needs to be a minimum load class of D400. 

Road drainage gullies – 

Road gullies are much larger than your bottle gully, however, the work in pretty much the same way. Our road gullies are made from plastic, creating a lightweight easy to use units. They act as liners for concreate castings, when all the correct pipework has been successfully connected. The concrete is used to provide extra strength and resist deformation.  

Road gullies are used to handle much heavier traffic in areas such as motorways, airports they are made with a trap that collects the sediment and stops any odours from getting out. Road gullies are used to hold rainwater, they are connected to the main drainage system, which will be discharged into a near by waterway. Road Gullies usually come with grids on top and an found along the side of most of the roads.

Gully Outlet | Polydrainage.co.uk

P trap gullies – 

P Trap gullies have been named for the P shaped bend in the centre , the reasoning behind this is brought to trap the water that flows into the gully. The water flows through the gully hopper and then enters a central chamber, connecting to the main drainage system. Having the bend in the middle of the system creates a barrier, stopping any gasses a foul smells getting out into the air. 

You can purchase P Trap bottle gullies in both 90° and 45°, they both function in similar ways. P Trap gullies usually come with a socket and rubber seal to allow you  to connect a pipe into it. However, sometimes they may arrive with out the need for a coupling to connect the gully to the drainpipe. 

The main difference between P Trap gullies and bottle gullies is that P Trap gullies are not roddable. 

PolyDrainage - 110mm Underground Low Back P Trap Gully

Bottle Gullies – 

The principle of bottle trap gullies are very similar to P Trap gullies. However, bottle gullies also known as compact, universal or yard gullies are distinctive for being roadable. This also means the central chambers within the trap are removable, making it much easier when you need to clean the gully, or remove any blockages. 

This is the more suited gully to homeowners as it is much easier to maintain, you can simply remove the trap, was it and replace it. 

Bottle gullies can come with either a fixed unit or with an adjustable top, which makes it easy for you to adjust the grid to the ground height. Plain ended gullies have one outlet to connect the gully to the sewage system. Back inlet gullies are designed to have an inlet on the back, allowing you to attach this to another drainage run. 

110mm Back Inlet Bottle Gully

Maintaining your gullies… 

To prevent any blockages in your gullies you need to keep up with the maintenance. It is suggested that you do so with seasonal checks, especially after a rainy or windy weather. Clearing out your gullies regularly is the key to ensuring your gullies last and an no unwanted smells arrive the gully will last as long as possible. 

However, if you are faced with a blockage, the method of removal is totally dependent on the type of gully installed. It is much easier to remove any blockages from a bottle gully due to the system being roddable and having a removable trap with an easy outlet pipe for access. To remove the blockage all you need to do is remove the chamber an insert your drainage rod this will allow you to dislodge the blockage. 

A P Trap gully on the other hand is a much harder unblocking. You will need to use a drainage specialist as they are more than likely going to use electronic mechanical pipe cleaning. 

Three elements make up sustainable drainage systems: prevention, drainage maintenance, and drainage. Here is how they function:

Drainage: This component of a sustainable drainage system collects rainwater from your lawn, directs it away from waterways and other sensitive areas, and stores it until it can be absorbed into the ground where it belongs.

Drainage Maintenance: This step in maintaining a sustainable drainage system entail keeping the area surrounding your home free of obstructions so that water won’t collect in one place or leak into pipelines and underground pipes.

Prevention: By collaborating with plants that naturally reduce run-off water before it reaches neighboring waterways and sensitive regions like stream banks or wetlands, this component of a sustainable drainage system helps prevent erosion.

How does it work?

The natural processes that take place when rainwater hits the ground are utilised by a sustainable drainage system. When precipitation contacts soil, it reacts with oxygen in the atmosphere and changes back into water. Our bodies receive nourishment from the food and liquids we consume through a process known as groundwater recharge.

Instead of flowing down a storm drain or directly into our waterways, where it may pollute them or be consumed by fish, the water in a sustainable drainage system returns to our subterranean water supply.

Why choose sustainable drainage systems?

A sustainable drainage system is a simple solution to reduce storm water runoff and improve the environmental friendliness of your home.

Does having a sustainable drainage system really help the environment?

A wonderful approach to save water is to install a sustainable drainage system. The main advantage of a sustainable drainage system is that it minimizes the volume of water that runs off your property into storm drains, which can cause flooding and erosion.

Main Benefits or using a sustainable drainage system:

Reduced runoff: A sustainable drainage system aids in reducing runoff by lowering the amount of precipitation that falls on your property annually, which can cause erosion and floods during periods of severe precipitation. By keeping pollutants out of waterways, sustainable drainage systems also aid in reducing pollution in nearby watersheds.

Water Conservation: A good strategy to save water is to install a sustainable drainage system. A sustainable drainage system’s key advantage is that it lessens the quantity of water that leaves your property and goes into storm drains, which can prevent erosion and flooding.

Additionally, a sustainable drainage system lessens the quantity of runoff into lakes, rivers, and streams. This translates into less waste being dumped into waterways and less damage being done to aquatic ecosystems.

Reduced Threats from Flooding: When compared to conventional solutions like earth dams or levees, a sustainable drainage system is more effective in preventing flooding, which helps shield your property from rising waters. Sustainability means that these systems can be constructed using components that are widely accessible across the nation, this means that their cost won’t be significantly greater than that of traditional alternatives.

Pollution Reduction: By lowering runoff from unmaintained areas like parking lots, highways, and other surfaces, a sustainable drainage system reduces pollutants. Additionally, it promotes stormwater infiltration so that runoff or stormwater overflow can be prevented, and the water can be absorbed by the soil and plants.

Soil Health: Sustainable drainage systems are fantastic for soil health because they reduce the quantity of surface water that drains off your land, which helps control excess runoff from your property. To prevent soil nutrients from evaporating into surrounding streams or draining away into subsurface aquifers, sustainable drainage solutions also help maintain soil nutrients in situ.

A sustainable drainage system has environmental advantages, but it can also increase crop yields by enhancing plant health and giving plants on your property better access to sunlight.

The Social Benefits of sustainable drainage systems: There are numerous ways in which a sustainable drainage system can benefit society and the environment. Reduced storm water runoff into nearby rivers during heavy rains, which can impact water quality and wildlife habitat, is one approach to do this (see above). It also benefits society by giving local workers jobs installing new drains.


Sustainable drainage systems have benefits for the ecosystem beyond just being good for the environment. They should be considered in your design plans for a variety of reasons, including less runoff and soil erosion as well as increased property value. Sustainable drainage systems are not just a passing fad; rather, they are an integral aspect of the growing sustainability movement that will affect all projects, large and small.

If you would like to receive any extra information surrounding our drainage pipes, you can send us an email at sales@polydrainage.co.uk

It goes without saying that flooding and severe weather can have a disastrous effect on the drainage system of your property.

The damage brought on by extreme weather can range from backed-up sewer lines to clogged gutters and downspouts, and it can be costly to fix.

Thankfully, there are precautions you may take to shield your drains from Mother Nature. Spending a little time preparing your drains for bad weather and flooding might help you avoid having to make expensive repairs later on. Any severe or out-of-season weather occurrence that results in property damage or fatalities is an extreme weather event, along with flooding. The most frequent sort of extreme weather is flooding, which can be brought on by strong rainfall, melting snow, flash floods, and broken dams. Tornadoes, hurricanes, thunderstorms, winter storms, and heat waves are all examples of extreme weather.

How to protect your drains…

Regularly having your drains professionally cleaned is one of the best methods to shield them from severe weather. Water can back up into your property as a result of clogged gutters and downspouts, causing significant water damage.

A professional drain cleaning business will have the equipment and knowledge required to clear your gutters and downspouts of any debris, ensuring that they can withstand even the heaviest downpours.

Alongside having your gutters and downspouts cleaned, you should take precautions to make sure that tree roots aren’t posing a threat to your sewer line. As they can grow into pipe cracks and obstruct sewage flow, tree roots are one of the most frequent reasons for clogged sewer systems.

Have a professional plumber evaluate the situation as soon as you can if you think tree roots may be interfering with your sewer line. Tree roots may often be cut without harming the pipe, but if they are too big or deeply ingrained, it might be required to replace the sewer line entirely.

Finally, if you live in a flood-prone area, you should take precautions to prevent water damage to your home’s foundation. The dirt around your foundation can be quickly eroded away by flood waters, leading to gaps that eventually let water into your basement or crawlspace.

You can help protect your drains from bad weather and flooding by following these easy actions. Regular maintenance and professional drain cleaning can greatly reduce the likelihood of future costly issues. Additionally, installing a sump pump can keep your foundation dry during even the worst floods if you reside in a flood-prone area. You can help protect your house from damage even during the most extreme weather conditions by acting right away.

The Problems caused by server weather.

Extreme weather conditions can cause drainage systems to flow more water than they are intended to, which may also create issues.

Storm drains can become overloaded by flash flooding and backed-up sewers due to heavy rains. Water may therefore back up into residences and establishments, causing significant harm. Extreme weather conditions have the potential to jeopardize people’s health in addition to causing physical harm. Sewage, chemical waste, and debris are just a few of the toxins that floodwaters might pick up when they flood a region. If this contaminated water encounters people or animals, it may subsequently spread diseases.

There are several strategies to protect against drainage issues brought on by severe weather. One is to make sure that your house or place of business has a drainage system that can handle the volume of water that is anticipated during a storm.

Another is to stay away from constructing in flood-prone locations. Finally, it’s critical to be aware of the dangers posed by extreme weather and to take precautions to shield your home and belongings from harm.

If you would like to receive any extra information surrounding our drainage pipes, you can contact email at sales@polydrainage.co.uk

Green Drain is now available to purchase! It is a globally multi-patented floor drain solution that allows the water to flow while blocking pathogens, gases, odours & pests. Currently it is the only product on the market that can protect businesses from pathogens like COVID-19.

It works by opening there valve to allow drainage water to pass through and close when there is no water flow. It can be used in either new construction or retrofit applications where trap primers were never installed.

The four flexible silicone sealing ribs ensure easy installation into openings that have variations in size. The green drain will open to allow drainage and close when there is no water flow and can be used in either new construction or retrofit applications where trap primers were never installed.

The product reduces exposure to hazardous sewer gases and disease-causing pathogens that harbor within drain lines and plumbing systems.  Our eco-friendly, preventative solution leads to improved outcomes for worker & patient health, while simultaneously exceeding the lifespan of traditional chemical applicants that harm the environment. Order this waterless trap seal today.

The Green Drain Prevents-

Product benefits: 

Product Features: 

You can find the product by clicking here.

For more information on Green Drain take a look at their website by clicking here.