Extensions in Highwoods

Extending in Highwoods

An estate built almost entirely in four years, which means one set of problems and, usefully, one set of answers.

Highwoods sits on the north east side of Colchester, west of Ipswich Road and wrapped around High Woods Country Park. Unlike most of the city it is not a suburb that accumulated. It was designed, argued over and then built in a single push, and nearly every house here shares a construction date, a roof type and a boundary arrangement with its neighbours.

That is genuinely helpful. It means the questions people ask about extending here have consistent answers, and the two that decide most jobs are what your garage is doing and whether your house counts as detached.

How it got here

A refusal, an appeal, an inquiry, and a country park that exists because of the argument.

The land west of Ipswich Road came to Colchester with a large housing allocation attached to it in 1974. The council refused the application on the grounds of harm, the developers appealed, and the case went to a planning inquiry in 1976 which they won. Building followed from 1981 into 1983 and 1984, with new family houses at around £32,000.

The interesting part is what came out of the negotiations. Land known as the southern slopes was secured rather than built on, and in 1987 it became High Woods Country Park, which is why an estate of this density has several hundred acres of woodland and grassland on its doorstep. An out of town superstore and the estate’s own local centre followed.

None of that is trivia. The country park is the reason the tree question here is a live one, and the compressed build programme is the reason the housing stock is so uniform.

Who decides, and what is missing

Colchester City Council, and for most of the estate no neighbourhood plan at all.

Applications go to Colchester City Council. What Highwoods does not have, and this separates it from its immediate neighbours, is a parish council of its own. Myland parish, next door, covers Braiswick across to Mile End and takes in a small part of Highwoods ward at its edge, so a handful of addresses here fall inside the Myland and Braiswick Neighbourhood Plan made in October 2023. The bulk of the estate does not.

Practically, that means the local plan and national policy are what your application is weighed against, with no additional layer of local design policy on top. It is one fewer document in the pile. It also means there is no parish council acting as a consultee on your behalf or against you, and the neighbours are the neighbours rather than an organised body.

The housing stock

Early 1980s detached and link detached, cavity walls, trussed roofs, and a garage attached to almost everything.

The typical Highwoods house is detached or link detached, two storeys, cavity walled with concrete interlocking tiles and a roof pitch on the shallow side. Gardens are usable rather than generous. Almost every plot has off street parking and most have a garage, either integral under the first floor or attached to the side and frequently sharing a wall or a roof with next door’s.

The roofs are trussed. Houses of this age were built with prefabricated frames rather than cut timber, and a truss cannot have a piece removed from it without ceasing to be a truss. Converting one of these lofts means substantially replacing the roof structure, and on the shallower pitches there is not the height to justify doing so. That is settled with a tape measure from the top of the ceiling joists to the underside of the ridge, and the honest answer on a good number of Highwoods roofs is no.

The compensation is what happens at ground level. These houses have a footprint, a driveway and a garage, and that combination produces the two most common jobs on the estate.

Detached, or link detached, and the metre it can cost

This is the Highwoods question, and getting it wrong costs a metre of extension or a retrospective application.

Permitted development sets different limits by house type. A single storey rear extension is allowed to project four metres from the original rear wall on a detached house, and three metres on anything else. The larger home extension route, which is a prior approval procedure with a neighbour consultation stage rather than a free pass, doubles those to eight and six.

A link detached house is joined to its neighbour by something, most often a garage. Whether it counts as detached for this purpose turns on whether the dwellinghouse itself is attached to another building, and that is a question of fact about your particular house rather than a label an estate agent applied to it. A house linked by a shared garage wall, a shared roof or a continuous structure is not automatically in the generous category, and the difference between four metres and three is the difference between the kitchen you drew and the one you get.

The way to settle it is not to argue about it afterwards. A lawful development certificate asks the council to confirm, before anything is built, that what you propose is lawful. It costs a fraction of an enforcement problem and it is the document a buyer’s solicitor will want in ten years. Our guide to the larger home extension prior approval scheme covers the longer route.

The garage, and the condition that may sit on it

The cheapest room in a Highwoods house, and the one most likely to have a planning condition attached.

An integral or attached garage already has a floor, a roof and three walls. Converting it is usually the lowest cost per square metre available on the plot, which is why it is such a common enquiry here.

Two things get in the way. The first is parking. Where the garage was counted towards the parking provision for the estate, a condition on the original permission may require it to be kept available for a car. That does not make a conversion impossible, but it makes it an application rather than a decision. The condition sits on the planning register against the original scheme, and it is checked before the drawings, not after.

The second is construction. Building Control treats the conversion as a material change of use, so the whole room has to reach current standards rather than the garage’s. The slab is usually uninsulated, often laid to a fall towards the door and sometimes without a damp proof membrane, so the floor is rebuilt rather than carpeted. The walls need lining and insulating. The opening left by the garage door is closed under the existing lintel with a properly built cavity wall, insulated and tied, rather than filled with blockwork and rendered over, which is the giveaway on a cheap conversion. Our garage conversions page goes through the sequence.

The park, the planting and the trees

An estate built in the early 1980s is now surrounded by trees planted in the early 1980s.

Two tree questions run here. The first is the country park and the woodland edge. Trees within it and along the boundary with it are mature, and a Tree Preservation Order may apply to individual trees or to groups anywhere on the estate. Where one does, work to the tree needs consent in its own right, on its own timescale.

The second is subtler and affects more people. Gardens laid out forty years ago have grown up. The sapling by the fence is now a full sized tree and the conifer screen planted for privacy has a root system to match. Where a new foundation falls within a tree’s zone of influence it has to be taken below the depth at which seasonal moisture change occurs, and that depth depends on the species, its mature height and its distance from the wall, not on how far the branches reach.

Taking the tree out is rarely the shortcut it looks like. Ground that has been dried by a tree for decades takes the water back when the tree goes, and swells. Heave acts upwards and does more damage than settlement. There is more in our guide to tree preservation orders and foundations.

Ground, and what is already on record

The one part of the job where a 1980s house is easier than an old one.

Estate housing from the 1980s onwards has foundations that were designed, inspected and recorded. The existing structure a new extension gets tied to is a known quantity rather than an archaeological question, which removes a whole category of surprise from the pricing.

What still has to be established is what sits under the new part. North Colchester carries glacial sand and gravel over London Clay, and which of them your trench finds changes both the depth and whether a soakaway will function. Granular ground drains and takes surface water; clay does not, and a soakaway sized on optimism rather than on a percolation test is a puddle waiting to happen. A trial hole answers both questions in an afternoon.

What people build in Highwoods

Three jobs account for most of the work, and each follows from the plot rather than from fashion.

Single storey rear extensions come first, sized by the depth limit and the fifty per cent rule rather than by ambition. Garage conversions are second, sometimes on their own and often combined with a small extension in front of or beside the old garage to make a proper room and a hall. Two storey side extensions are third, on the plots with room beside the house, which on this estate means the ones on corners and at the end of a run.

Access is the quiet advantage. Driveways, side gates and space to stand a skip on your own ground are normal here, and that is worth real money against the same drawing built on a terrace where everything comes through the hall, as it does on the older stretches of Mile End Road.

Questions we get asked in Highwoods

Is my house detached?

It depends on how it is joined to the one next door, and it is worth resolving before the drawings rather than after the dig. The difference is a metre of depth under permitted development.

Can I convert the garage without applying?

Often, but check the original permission first. Where a condition requires the garage to be retained for parking, an application is needed to remove or vary it.

Is the loft worth doing?

Measure the ridge height first. Where it is there, the trusses can be replaced with a structure that leaves a usable room. Where it is not, the money is better spent at ground level.

Does the country park affect my extension?

Not in itself. Trees do, whether they stand in the park, on the boundary or in your own garden, and protected trees carry a separate consent.

Getting a price for a Highwoods extension

We work out of West Bergholt, on the other side of the city, and Highwoods is a short enough run that we can be there to look at something rather than describing it over the phone.

Our team comes out, establishes how the house is attached to its neighbour, what the garage is doing, what the roof will and will not give you, and where the trees and the drains are. We check the planning history of the address for conditions before anything is drawn. From there the technician draws it, the structural engineer we work with calculates it, we handle the certificate or the application with Colchester City Council, 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.