Can I cover the unsightly manholes in my garden?

My back garden has three manholes which are rather unsightly. Can I cover these with grass or something else, or do I need to allow for access? Do you have any recommendations for how we might cover them if it is permissible?

This is a point dear to my heart. I love my garden, and concrete chamber covers and manholes – in my case, Armstrong junctions – can jar with the perfect pastoral or urban-Eden look. In many cases they can be too proud of the lawn, popping up to let everyone know just what happens in that part of the garden. As a result, they have to be negotiated with a lawnmower or left to the strimmer. It can also lead to the barbecue being repositioned to a less favourable spot as you don’t want your guests holding forth on an iron slip-resistant disc.

Nevertheless, we have to pause and look at why they are there in the first place. The consequences of not having a functional drainage system in terms of surface water can be disruptive and, in a worst-case scenario, may damage a building. Also, the consequences of having a dysfunctional wastewater drainage system may result in a hazardous outcome. When constructing dwellings, or indeed any building that has a requirement for drainage, there are regulations. Part H of the building regulations technical guidance document (TGD) on drainage and wastewater disposal deals with many aspects of drainage. Design for maintenance, including rodding, is clearly stated within the TGD. This ensures a functioning drainage system.

A manhole cover, as opposed to, for example, an Armstrong junction (smaller access points, usually with a square cover which facilitate the inspection of a house’s sewer pipe) can sometimes point to a larger system and yours may be part of a larger scheme taking in other properties.

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Again, you may have to consider the “why” in terms of others that have a stake in the system and possible rights-of-ways associated with it. Regardless of it being your system only or a many-partied system, however, access points must be readily identified and be able to be accessed in good time and allow enough room to facilitate servicing.

Anyone who has had drainage or blockage issues will have a full appreciation of how important this is. Covering them with grass would not be in your interest and not in the interest of your neighbours if it’s part of a larger scheme.

However, all is not lost. Where a manhole cover is perhaps too proud of your lawn and sitting up for all to see, you could consider reducing or lowering the walls of the manhole and making the lid flush or level with your lawn. If the system is in the charge of the council, they may do this at your request. If not, you could engage a suitably qualified fully-insured contractor.

Where the drainage pipes within the manhole chamber do not allow for a reduction, raising your lawn level in line with the manhole cover may reduce the negative impact and offer an aesthetic reprieve. You could also place pots or planters on the lid without fully obscuring it or preventing easy access.

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Decorative proprietary covers can also be installed over the manhole cover that are designed to be easily lifted to access the manhole. These can look well in a patio setting. Hopefully one of these suggestions works for you and increase the enjoyment you derive from your back garden.

Brigid Browne is a chartered building surveyor and a member of the Society of Chartered Surveyors Ireland.

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