Look Down: A Walk Round the Ground Beneath a Listed House

Before you lay a path, raise a flower bed or replace a floor in a listed house, look down. Check where the ground sits against the walls, where the rain goes, and whether the work touches the listing at all. Consent can be needed for works outside the walls as well as inside them, and your own council decides.

That is my judgement, and it is where I would start. Earlier this week I wrote about damp in an old house, which ended with the idea that a happy old house is one that is allowed to dry. This one follows the water down to the place it usually goes wrong.

Start at the foot of the wall

Walk round the outside slowly, and keep your eyes between your knees and the ground. I am not looking at the architecture yet. I am looking at the line where wall meets earth, because that is where an old house tells you how it has been treated.

What I notice, in this order:

• whether the soil, paving or gravel has crept up the wall over the years
• which way every path and patio falls, towards the house or away from it
• where the downpipes empty
• whether the base of the wall is stained, flaking or green
• whether anything hard has been poured against the wall

Old stone floors were laid to move moisture, not to stop it. Photo: ⋆ ˚｡𖦹 on Unsplash

Stand with your back to the house

A house settles into its garden over centuries. Paths get re-laid a little higher each time, and a flower bed is always easier to top up than to dig out. The trouble starts when the outside ground rises to meet the floor inside.

West Suffolk Council's conservation leaflet describes that moment: ground level outside "allowed to build up until it is at the same level or higher than the internal floor". Its remedy is that high external levels "should be lowered so they are below the level of the floor inside the building", with the warning to take "care not to undermine shallow foundations". It also advises that external paths should slope "away from the walls of the building to channel rainwater away", and says concrete paths laid round the outside "can prevent moisture from evaporating".

I read that as a warning against doing the obvious thing quickly. Lowering a path by a few inches sounds easy. In an old house, I would want to know how deep the footings go before a spade goes in, and I would not dig on a guess.

If the gutters and downpipes were the culprit, start there: I wrote about repairing gutters on a listed building earlier this month. It takes water away from the wall at its source, and it asks the least of the building.

Is the path part of the building?

It can be. People are often surprised by how far a listing reaches. Section 1 of the 1990 Act treats as part of a listed building "any object or structure fixed to the building", and any object or structure within its curtilage which "forms part of the land and has done so since before 1st July 1948". GOV.UK's planning practice guidance adds that listing, unless the list entry says otherwise, "covers the entire building, internal and external", and may include curtilage buildings and structures.

Section 7 is the gate: no one may carry out works to a listed building for "its alteration or extension in any manner which would affect its character" unless they are authorised. The Planning Portal puts the everyday version plainly: "you will need listed building consent for any significant works whether internal or external". For paving, it also notes that "significant works of embanking or terracing to support a hard surface might need a planning application", and that "different rules apply to paving over your front garden".

None of that tells me whether your new terrace needs consent. It tells me the question is worth asking before the work, not after. An old garden wall, a historic yard surface or a cobbled apron may itself be part of what is listed, so look at the list entry and ask your own council's conservation officer.

Then go indoors and look down

The same logic holds under the floorboards and under the stone. West Suffolk's leaflet recommends that concrete floors "should be replaced where possible" with a breathable floor, and, where the whole floor cannot be replaced, "making a breathable channel around the edge of the room". I would put it more cautiously than a leaflet can: an old floor was laid to let moisture move, so cover it with something that cannot move moisture and the moisture will find another way out, usually through the wall beside it.

This is why I like to ask a plain question before a floor is dug up: does it need to be? A worn flag, a lime floor or a brick floor with some character may be exactly what the house is supposed to have, and repairing it may be a better answer than replacing it. If a new floor is warranted, the build-up and the depth of excavation matter far more than the finish. That is a design decision, and it is one of the moments where an architect earns a place.

A short checklist for the walk

What I look at	Why it matters	Who I would ask
Ground against the wall, compared with the floor inside	High ground can push water into the wall	Your council's conservation officer, before digging
The fall of every path and patio	Water should run away from the house	A builder familiar with old buildings, once the aim is agreed
Concrete or hard coatings round the base	They can trap moisture in the wall	A heritage architect, who can look at cause as well as symptom
The floor inside, and what is under it	An old floor is part of how the building breathes	The list entry first, then the council
Historic surfaces, steps and garden walls	They may be part of the listing	Your council, with the list entry in hand

Where I would stop and ring someone

I would happily clear a gully, cut back planting that touches the wall, or rake gravel clear of the damp course. I would stop before digging beside a wall, lifting an old floor, pouring concrete or moving a boundary wall. Whether any of it needs consent depends on your list entry, your council and your building, and I cannot tell from here.

If you would like a view of how this fits with the rest of the house, my piece on what a heritage architect looks for on the first visit describes how I read a building before any drawing. If your house is in Hertfordshire, there is more on how we work there on the Hertfordshire page.

An old floor was laid to let moisture move, so cover it with something that cannot move moisture and the moisture will find another way out.

Most old houses have been quietly good at managing water for a very long time. I am hopeful that a little attention at ground level is usually all they ask.

Speak to Giles if you would like a second pair of eyes on the ground round your house: book a conversation, get in touch, call +44 (0)7737 745211, or send a WhatsApp voice note.

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Giles Paul Shorter — ARB registered · RIBA member · on the RIBA Conservation Register · 17+ years specialising in listed and historic buildings.