Extensions in Dedham

Extending in Dedham

The village on this list where the designations cover everything, and where two separate consent systems routinely apply to one job.

Dedham sits on the Essex bank of the Stour about five and a half miles north east of Colchester. The parish held 1,992 people at the 2021 census. It stopped growing when the cloth trade faded and the railway was built somewhere else in the 1840s, and that is the reason the High Street still looks the way it does.

The planning position is easy to state and demanding to work with. The village lies inside the Dedham Vale National Landscape and inside the Dedham conservation area. Around a hundred buildings in the parish are listed, and roughly half of those stand on or immediately around the High Street. A great many Dedham addresses sit under two designations at once, and a good number under three.

Who decides

Colchester City Council, and it is worth saying so plainly because the Suffolk border is a field away.

Dedham is a civil parish in the City of Colchester district, so applications are determined by Colchester City Council. Dedham Parish Council is consulted and does not decide. The Stour is the county boundary here, and the villages on the far bank answer to a different district in a different county, which is covered on our neighbouring pages where it applies.

That matters for a practical reason rather than a constitutional one. Planning application fees are set nationally, so those do not change at the boundary, but validation requirements, the local list of drawings, pre-application charges and the building control service all do. Getting the right one first time is not clever; getting it wrong costs you a month.

Two designations, stacked

One of them changes what you may do without applying. The other changes how the application is judged.

Dedham Vale was designated an Area of Outstanding Natural Beauty in 1970 and renamed a National Landscape in November 2023. The legal designation did not change with the name, and planning documents still use the AONB term.

Land inside it becomes what the legislation calls article 2(3) land, and that is a specific, checkable consequence rather than a general atmosphere of restraint. Under Class A of the permitted development order, on article 2(3) land:

• a side extension is no longer permitted development at any width;
• a rear extension of more than one storey is excluded, so a two storey rear addition is an application;
• cladding the outside of the house is excluded;
• the larger home extension prior approval route under paragraph A.4, which is the one that doubles the depth allowance at the back, is not available at all.

Class B, which covers enlargements of the roof and therefore dormers, does not apply on article 2(3) land either. Class C, which covers other alterations to a roof, carries no such exclusion, so a rooflight sitting in the plane of the existing slope stays permitted development, front slope included. It has to sit no more than 150mm beyond the plane of the original slope, no higher than the highest part of the roof, and be obscure glazed where it faces a side elevation. Our guide to permitted development rights takes the classes in order.

The conservation area is the second layer and it works differently. It does not remove those rights again, because they have already gone. What it adds is control over demolition, a six week notice requirement before work to trees above the size threshold, and an officer assessing materials, proportions and detailing rather than only bulk. The conservation area guide sets out what survives and what does not.

The boundary of the National Landscape crosses the south of the parish towards Dedham Heath, so a small number of addresses at that end fall outside it, in the same way the line leaves most of Langham outside. That is checked against the address rather than assumed from the village name.

The listed buildings, and what listing does not do

The most repeated misunderstanding in this village is that a listed house has no permitted development rights left.

It is not true. Listing does not remove the Part 1 rights that govern extensions and roof work. What listing adds is listed building consent, a separate control under separate legislation, covering anything that affects the special interest of the building, inside as well as out. Carrying out work that needs it without having it is a criminal offence, not a planning breach to be regularised later.

In practice that second consent is much the harder of the two, which is why people assume the first has gone. It reaches further than most owners expect. Internal joinery, a chimney breast, a partition, a staircase and a floor structure are all within it. So are buildings within the curtilage that were there before July 1948, which in Dedham means a good many outbuildings, walls and former workshops behind the High Street frontages. Our page on extending a listed building covers curtilage and setting properly.

The other thing worth knowing is that the listing is of the whole building, and the description in the entry is not the limit of what is protected. A short entry does not mean a lightly protected house.

The other Dedham

Most extension work in this parish happens on houses nobody photographs.

The historic core is genuinely exceptional. Timber framed halls with plastered walls and tiled roofs stand near the church and the manor, with cross wings and jettied bays from around 1500 surviving in buildings along the street. The long rear ranges running back from the High Street were the cloth trade’s working space. In the sixteenth and seventeenth centuries these were remodelled into L plans with jettied fronts turning down Mill Lane, and decorated with strapwork pargetting and moulded plaster ceilings.

The Georgian century refaced rather than rebuilt. Brick fronts went on, frequently only a skin over the frame behind, in white Suffolk and rubbed red brick, with five bay elevations and pedimented doorcases on the better houses. Early nineteenth century work used gault or white Suffolk brick. Then in the early twentieth century a good deal of the timber work was deliberately re-medievalised, with salvaged material reused and later fronts stripped off. The consequence for anyone opening up a wall is that the date on the outside is not reliable evidence of what is behind it.

Beyond that core is a twentieth century village. Council housing went up at Crown Fields after the First World War. Post-war building included Airey houses, a prefabricated system with a reinforced concrete frame and concrete panels rather than masonry walls. Private estate building peaked in the 1960s, and since then most new floor space has come from infill and conversion.

The concrete houses matter if you own one. Where a house of that type has not been reconstructed under a licensed repair scheme, you cannot tie a new extension into the wall in the ordinary way, the structural answer is different, and lenders treat the house differently too. It is the first thing to establish, before anything is drawn.

The ground, which changes as you walk south

Three different subsoils inside one parish, and the difference is a foundation depth rather than an academic point.

The land rises from under 8 metres beside the Stour to about 38 metres on the flat plateau of Dedham Heath, and to 46 metres at Birchwood in the south west corner. River gravel underlies the town itself. Alluvium fills the Stour meadows. London clay covers much of the ground towards the heath, and the heath carries a glacial drift of sands, gravels, loam and brickearth, which was dug commercially from the sixteenth century onwards.

So the honest answer to what a Dedham foundation costs is that it depends which end of the parish you are at. On gravel, bearing can be reached at a sensible depth but the trench sides will not stand and groundwater needs managing while concrete goes in. On London clay, depth is set by seasonal moisture change and by any mature tree within influencing distance, and 900mm is rarely enough near one. On alluvium next to the river, neither assumption holds and the design starts with a trial hole. Our guides to extension foundations and Essex clay and heave go through the types and what each one solves.

Water, and where it goes

The Stour is the obvious one. The brook running across the middle of the parish is the one people forget.

Dedham is inside a formal flood warning area covering the Stour from Boxted downstream, and the low ground by the river and the mill has a real flood risk attached to it. Before the pumping stations went in during the 1960s the valley flooded regularly, and the Black brook still runs east to west across the centre of the parish on its way to the river.

A householder extension in a flood zone is treated as minor development, so the sequential test does not sit in your way. The response is in the construction rather than the paperwork: floor level set deliberately, a solid floor, services lifted, and materials low down chosen because they will dry out rather than because they are cheap. Our guide to flood zones and extensions in Essex explains how the levels are established.

Getting materials in

On the High Street there is often no side access at all, and the street was not designed for a lorry.

The historic frontages sit on the back of the pavement in a continuous run, with the plots stretching a long way back. Where there is no gate down the side, everything goes through the house: bricks in, spoil out, by hand. That is not a small adjustment to a price, it is a different job, and any quotation that has not looked at the passage down the side has not priced the work you are asking for.

Add the visitors. Dedham is a destination, the parking is finite, and a skip on the street needs a permit from the highway authority. Deliveries get booked for the quiet end of the day, and a wagon that cannot turn is a wagon that goes home full.

What people build in Dedham

The designations push almost everything to the back of the house, which is usually where it belonged anyway.

Single storey rear extensions lead, because they are the one thing still capable of being permitted development on the twentieth century stock, and because on the historic plots the rear is where change is least visible from the street. Opening a small cellular plan into one kitchen and living room accounts for most of the enquiries.

Roof work comes second, and it is nearly all rooflights rather than dormers, for the reason set out above. On the older houses that is often the only sensible answer anyway, since a dormer on a steeply pitched historic roof rarely improves it.

After that, garden buildings and outbuilding conversions. Inside the designated area an outbuilding sited more than twenty metres from any wall of the house is capped at ten square metres in total, which changes the answer on a long plot, and where the outbuilding is a pre-1948 structure in the curtilage of a listed building the second consent applies to it as well.

Questions we get asked in Dedham

My house is listed. Have I lost permitted development?

No. Listing adds listed building consent as a second and stricter control; it does not take the Part 1 rights away. In Dedham the designated land does remove several of them, but that is the National Landscape doing it, not the listing.

Can I put rooflights in the front slope?

Generally yes, within the size and projection limits, because the class covering rooflights carries no exclusion for designated land. A dormer in the same slope is a different class and does need permission here.

Is the whole village in the conservation area?

Not quite, and the line does not follow the obvious roads. It is checked against your address, along with the National Landscape boundary, before anything is designed.

Can I use the six metre rule at the back?

Not on land inside the National Landscape. The larger home extension route is unavailable there, so the ordinary Class A depth is the limit unless you apply.

Getting a price for a Dedham extension

We are at West Bergholt, a few miles round to the west, so this is a short run rather than a trip out to a postcode on a coverage list.

Our team comes and looks at the actual house: what the walls are made of, where the frame sits behind the render, whether there is access down the side, what the ground does at your end of the parish, and exactly which designations land on your address. Most people who call us already have drawings and permission and want a builder to price the work and build it. That is the ordinary job here, and we are glad to work to somebody else’s plans. Where the drawings do not exist yet, we bring in the technician who draws it and the structural engineer who calculates it, we handle the application with Colchester City Council and any listed building consent alongside it, we notify Building Control, and we run the job as main contractor.

We carry £2m public liability cover and build to current Building Regulations, through to the completion certificate. The survey and the quotation cost nothing.