Extensions in Marks Tey

Extending in Marks Tey

A road cut this village in half in 1971, and it cut the housing stock in half with it.

Marks Tey had around 800 people in 1964. By the early 1970s it had roughly 2,300, and by the 2011 census 2,551. That growth did not happen gradually. Demolition for the A12 bypass began in May 1968, taking out cottages, the post office, the general stores and the main entrance to the railway station, and when the road opened in 1971 the village was left in two pieces with a trunk road between them.

People here still talk about old Marks Tey and new Marks Tey, and the distinction is not sentimental. The old side is the earlier ribbon along the London Road, mixed in age and plot size. The new side is the estate built to rehouse and expand the village around the same time, roads like Mandeville Close and Hawlmark End, laid out to a single plan with a school opened in 1966. They are two different extension jobs.

The ground here is not the ground in Colchester

Marks Tey sits over a buried lake, and it is the reason there has been a brickworks here for generations.

This is the part of the page worth reading twice, because almost every extension quote written for this area is priced on assumptions about Essex clay that do not transfer cleanly to this village.

Beneath Marks Tey is a deep, narrow trough cut into the ground by ice, which filled with water during the Hoxnian interglacial around 400,000 years ago and then filled slowly with sediment. What sits in it is laminated clay mud, layer on annual layer, resting on chalky boulder clay. It is a nationally important geological site: the brickpit is a Site of Special Scientific Interest of about 29.5 hectares, and the clay is still worked for brickmaking.

Three things follow for anyone digging a foundation.

• Laminated lake clay is a fine grained, high plasticity material. It shrinks and swells with moisture change like any clay, and where trees are nearby the influencing distances are the ones used for the most shrinkable soils rather than the middling ones.
• The trough has steep sides, so the depth to competent ground can change substantially over a short horizontal distance. Two plots on the same road are not necessarily the same dig.
• Made ground is a real possibility near the old workings and near the line of the bypass, where the road was cut through and material was moved.

The practical answer is not exotic. It is that the trial hole and the engineer’s calculation decide the foundation here rather than a rule of thumb, and that a quotation which does not say what depth has been allowed for is not a quotation for this village. Our foundations guide sets out how the depth actually gets chosen, and the clay and heave guide covers what happens when a tree is removed from ground it has been drying for decades.

The housing stock, by side of the road

Pre-war ribbon on one side, planned early-1970s estate on the other, and later infill threaded through both.

The older frontage along London Road runs from genuinely historic buildings through Victorian and Edwardian cottages to interwar houses, in no particular order and with no consistent plot depth. Some have generous gardens behind, some have almost nothing. Side access is a plot-by-plot question.

The estate housing from around 1966 to the mid 1970s is much more uniform: two storey semi detached and terraced houses and a scattering of bungalows, brick with some tile hanging, shallow trussed roofs, modest but usable rear gardens, and the layout logic of the period, which means culs-de-sac, footpath links and parking in courts as often as on the plot. Later infill has gone into the gaps in both halves.

That 1970s stock has a specific and often overlooked feature. Roofs from that period are frequently trussed rafters at a shallow pitch, and a straight loft conversion is rarely possible without replacing the roof structure entirely. Where the ridge height genuinely will not give 2.2 metres or so over the stair landing, the honest answer is that the money is better spent going out at ground level.

The neighbourhood plan, made April 2022

Marks Tey has its own development plan document, and design is one of the things it covers.

Colchester City Council is the planning authority. Marks Tey Parish Council comments on applications and does not decide them, but it has done something that gives it real weight: the Marks Tey Neighbourhood Plan went to referendum in May 2022 and became part of the development plan, as neighbouring Great Tey‘s did in 2024. Its policies include village settlement boundaries, local character and design, landscape character, heritage assets and green infrastructure.

For a householder application that means the design policy in the neighbourhood plan is applied alongside Colchester’s Policy DM13 on domestic development. DM13 asks whether the extension is compatible with the scale, appearance and character of the original dwelling, whether it is subordinate to it, whether the plot becomes overdeveloped and what the cumulative effect across the street would be. On a uniform 1970s estate that last test carries more weight than people expect, because the street reads as a set rather than as a row of individual houses.

There is no conservation area recorded over Marks Tey and no Article 4 direction recorded over it, unlike neighbouring Copford Green. The listed church of St Andrew, whose nave dates from around 1100 and is built of mixed rubble, puddingstone and reused Roman brick under a timber tower, is the parish’s most significant heritage asset, and its setting is a consideration for anything built close to it.

Living beside a trunk road and a main line

Noise is a design problem here, and it is worth being clear that it is not a Building Regulations one.

Marks Tey has the A12 through the middle, the A120 at Coggeshall Road, and the Great Eastern Main Line with the junction for the Sudbury branch. A rear extension on the wrong side of a plot can be noticeably louder than the room it replaced.

The regulations do not solve this for you. Approved Document E deals with sound passing between and within dwellings, not with traffic noise coming in from outside, so nothing in the Building Regulations sets a standard for the glazing on the back of your house. It is a specification decision: laminated acoustic glass in the elevations that face the noise, attention to how the trickle ventilation is achieved, and a roof build-up with some mass in it rather than the thinnest that meets the U-value.

Overheating is worth the same clarity. A large, heavily glazed extension facing south will get hot, and Approved Document O, which covers overheating, applies to new residential buildings rather than to an extension of an existing house. So there is no regulatory backstop here either. Shading, glazing specification and a way of getting air through the space are design choices you make, or design choices you regret.

Where the rainwater goes

On this ground a soakaway is usually the wrong answer, and it is worth establishing that before the drawings say otherwise.

A new extension roof plus a new terrace produces a surprising volume of surface water, and it has to be disposed of somewhere the Building Regulations recognise. The default drawing shows a soakaway, because on free draining ground a soakaway is cheap and simple.

Laminated lake clay is close to the opposite of free draining. A percolation test on it will frequently fail, and a soakaway that fails a test is not a soakaway, it is a hole that fills up in November and stays full. Where that is the case the water has to go to a surface water sewer or to a watercourse, which is a different conversation with different costs and sometimes a different consent.

The foul side has its own trap. Older estate drainage often runs across the rear gardens serving several houses, and a shared run is a public sewer for these purposes even where it sits entirely within one garden. Building over it, or within three metres of it, needs a build over agreement from Anglian Water, which is a separate application on its own timescale and can require a survey of the pipe or a foundation designed to bridge it rather than load it. We lift the covers and follow the falls at survey, because finding it with the digger on site is the expensive version. Our build over guide explains how the agreement works.

Access and logistics

The village is easy to get to and awkward to get around, and the two halves are awkward in different ways.

Marks Tey sits at the A12 and A120 junction with a station on the main line, so materials and trades arrive without difficulty. The problem is local. Coggeshall Road and the approaches to the junction carry heavy traffic at predictable times, and a lorry that turns up at half past eight will sit in it. Deliveries get booked around that rather than into it.

On the estate roads, parking is the constraint. Houses of that period were planned for one car and now hold two or three, so kerbside space is contested and a skip on the road needs a permit and a plan. Where a plot has a driveway, keeping the skip and the material stack on it is worth the small extra handling.

On the older London Road frontage the constraint is frontage width and a busier road. Some plots have no side access at all, and where everything has to come through the house, that is a cost line rather than an inconvenience.

What people build in Marks Tey

Ground floor work, mostly, and for a structural reason rather than a fashionable one.

Single storey rear extensions dominate, usually to make a kitchen and family space across the back. On the estate housing the flat roof with rooflights is common, because a pitched roof would run into first floor windows on houses of that depth.

Two storey side extensions appear on the wider plots on the older frontage, where there is genuine width beside the house. They are nearly always a full application, and the design conversation is about setting the front face back and keeping the ridge down so the original house still reads as the original.

Garage conversions are steady work on the estate stock. Where the garage is attached, the job is insulation, floor build-up, a lintel and a proper opening. Where it stands in a block with the neighbours’, it is not available at all.

Questions we get asked in Marks Tey

Is my foundation going to be deeper because of the brickpit?

Not because of the pit itself. Because of what is under the whole village, which is a deep clay-filled trough rather than uniform ground. Depth comes from the trial hole and the engineer’s calculation, and it is genuinely worth doing here rather than assuming.

Does the neighbourhood plan mean the parish council decides?

No. Colchester City Council determines the application. The neighbourhood plan means the parish’s own design policies form part of what Colchester has to decide against.

Can I convert the loft in a 1970s house?

Sometimes, and less often than people hope. Measure from the top of the ceiling joist to the underside of the ridge before anything else. If the trusses have to come out and the roof has to be rebuilt, the cost stops looking like a loft conversion.

Will the extension be noisy from the A12?

It depends where on the plot it sits and what you glaze it with. It is a solvable problem and it costs more to solve after the frames are ordered than before.

Getting a price for a Marks Tey extension

We are based at West Bergholt, on the other side of Colchester, and Marks Tey is straightforward ground for us to work on.

Our team comes out and surveys properly: the ground and what a trial hole shows, the trees, the access, the drain runs, the roof structure where a conversion is being considered, and the planning position on your specific 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 to Colchester City Council where one is needed, we notify Building Control, and we run the job as main contractor.

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