Double Storey Extensions in Milton Keynes
Two storey rear and side extensions across Milton Keynes, adding living space below and bedrooms above in one build.
If the budget stretches, two storeys is almost always the better value. The foundations, the drainage and the roof are the expensive parts of any extension, and a second storey shares all three. You get the kitchen you wanted downstairs and a fourth bedroom or a proper ensuite above it, for a good deal less than doing the two jobs separately.
Typical works can include
Every project is different. Depending on the agreed scope, works may include:
- Engineer designed foundations to suit the two storey load
- Cavity blockwork and matched facing brickwork over two storeys
- First floor joists or steel, and the upper floor structure
- Pitched roof married into the existing roof, with matched tiles
- Openings into the existing house at ground and first floor
- Windows, doors, bifolds and rooflights
- Ensuite plumbing, electrics and first fix throughout
- Plastering, flooring, decoration and finishing carpentry
- Building Control and Party Wall liaison, where required and where included within the agreed scope
Elements such as decoration, flooring, structural engineer fees, Building Control fees and any professional or design costs are dealt with according to the individual project, and are included only where the quotation says so.
Planning: usually an application
A double storey rear extension can fall within permitted development, but the limits are tight: no more than 3 metres deep, at least 7 metres from the rear boundary, matching roof pitch, and no side facing windows on the upper floor unless they are obscure glazed. Most of the two storey work we do in Milton Keynes goes through a full planning application to Milton Keynes City Council instead, and on the newer estates permitted development rights have often been removed anyway.
A two storey side extension almost always needs planning permission, and the council will look at how it sits against the neighbour and whether it closes the gap in the street. Setting the first floor back from the front and keeping the ridge lower than the main roof usually keeps everyone happy. As ever this is general guidance; the position depends on your property, and we will point you at the council or a planning professional where it needs confirming.
The structure and the roof
Two storeys means real load on the foundations, so they are designed by the engineer rather than assumed, and on Milton Keynes clay near trees they go deep. The first floor goes in on joists or a steel, the upstairs opening into the existing landing or bedroom needs its own beam, and the roof is the part that decides whether the extension looks right from the road.
On a house with a trussed roof, which is most of the city, the new roof has to marry into the existing one without cutting the trusses, so the junction is designed properly with a valley or a hip. Getting the tile match, the fascia line and the gutter levels right is the difference between an extension and a house that was clearly built that way.
Party Wall matters
On a semi or a terrace, two storey work against or near the shared wall, or foundations within 3 metres of it and deeper than the neighbour’s, can fall under the Party Wall etc. Act 1996. It is framed as a possibility rather than a certainty, because it depends on the design. We will tell you early if we think notices are likely so they can be served in good time.
Living in it during the build
Most people stay. We build the shell outside first, get it watertight, and only then open up into the house, downstairs and then up. There is usually a week or two where the upstairs is dusty and the landing is boarded, and a kitchen out of action for a while at the end. We tell you the dates in advance so you can plan around them.
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Examples of this work
Some of these are mid build rather than finished, because that is where you can see how something was put together.
Worth knowing
Two storey work takes longer and the planning stage can add two or three months before we start. If you need the space by a fixed date, start the drawings early. And if the upstairs room only needs to be a box room, ask us whether a single storey extension and a loft is the better route. Sometimes it is.
Where we do this work
Milton Keynes is home and most of this work is inside the city. We also take it on across the surrounding towns, and each of these has its own page on what the job tends to involve there.
Every area we cover, and what is different about building there
Common questions
Will I need planning permission for my extension?
Often not. A single storey rear extension can usually go to 3 metres on a semi or terrace and 4 metres on a detached house under permitted development, with a 4 metre height limit and a tighter one within 2 metres of the boundary. You also cannot cover more than half the land around the original house.
The Larger Home Extension route can take those depths further, but it requires prior approval from Milton Keynes City Council before work starts and that process takes time. Conservation areas, listed buildings and properties that have had permitted development rights removed are all different again.
This is general guidance rather than planning advice, and the position depends entirely on your property and what has been built before. We can flag the likely requirements at the first visit and advise when confirmation should be obtained from the council or an appropriate professional.
Do I need to tell my neighbours?
Legally, sometimes. The Party Wall etc. Act 1996 applies if you are building on the line of junction, cutting into a shared wall, or excavating within 3 metres of a neighbouring building and deeper than their foundations, or within 6 metres on the 45 degree line. Notice has to be served in advance: one month for excavation, two months for party structure work.
Practically, always. Even where no notice is required, telling next door what is happening and roughly when is the difference between a neighbour who tolerates the noise and one who complains to the council. We keep sites tidy and the road clear.
How long will the work take?
It depends on the job, and anyone who gives you a number without seeing the house is guessing. As a rough guide: a bathroom is two to three weeks, a kitchen refit two to four, a single storey rear extension is usually ten to fourteen weeks from breaking ground, and a full house renovation runs three to six months depending on scale.
Weather, Building Control inspections and lead times on windows, doors and kitchens all move those numbers. We build realistic float into the programme rather than promising a date we cannot hold.
Can we stay in the house while you work?
Usually yes, and most of our customers do. On an extension you can live fairly normally right up until we break through into the existing house, which we leave as late as possible for that reason.
On a full renovation it is harder but still workable. We go room by room, keep a working kitchen and bathroom going as long as possible, sheet up properly and clean down at the end of each day.
Related work
Single storey extensions
The most common extension we build, and the one with the most options.
Read moreHouse extensions
Single and double storey extensions, built and managed start to finish.
Read more
Side and wraparound extensions
The gap beside the house, and the L shape when you go round the corner.
Read moreTalk it through before you commit
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