Design, Calculations and Building Control
House Extensions in Fleet
Underneath Fleet the ground is commonly London Clay with overlying Bagshot sands, so the ground can change noticeably over a short distance, and what a foundation or a bearing has to do depends on it. Open Plan Homes Limited carries out house extensions across Fleet, designing against what a site investigation actually shows rather than against a standard detail.
We start with a look at the property itself. Once we know what is load bearing and what is not, we can set out the scope and a written figure, which is a very different conversation from an estimate given over the phone.
Fleet, Hampshire
Local Considerations for House Extensions in Fleet
- Planning authority
- Hart District Council
- County
- Hampshire
- Typical ground
- London Clay with overlying Bagshot sands, so the ground can change noticeably over a short distance
- Party wall exposure
- Detached and semi detached stock dominates, so many Fleet projects involve one adjoining owner rather than two, and a fair number involve none at all.
Not every street in Fleet presents the same problem. Nearer Fleet Pond, Fleet Road and Elvetham Heath you are typically looking at Edwardian and interwar villas around Fleet Road and the streets nearest Fleet Pond, while away from that older core the town runs to large 1960s to 1990s estates, plus the more recent Elvetham Heath and Crookham Park developments. The difference is not cosmetic: it changes how a wall is built, what it carries, and how an opening in it has to be supported.
Hart District Council is the local planning authority, with Hampshire County Council above it for highways matters such as skip permits and any scaffold that reaches the pavement, and that is who any application goes to. Alongside the general position, Hart applies tight controls around the Fleet Pond Site of Special Scientific Interest, and the Thames Basin Heaths Special Protection Area sits close by, both of which can matter where a project creates additional dwelling space rather than simply reorganising it. Where that applies to a property, the sequence has to run heritage first and structure second, because the acceptable solution can be narrower than it would otherwise be.
Detached and semi detached stock dominates, so many Fleet projects involve one adjoining owner rather than two, and a fair number involve none at all. The ground is another factor: across Fleet it is commonly London Clay with overlying Bagshot sands, so the ground can change noticeably over a short distance, and while that is a general picture rather than a promise about any one plot, it shapes what a foundation or a padstone detail has to achieve. This is our own doorstep, since the office is on Reading Road South, so a Fleet site visit is usually the easiest one in the diary to arrange at short notice.
What is included
House Extensions in Fleet: What Is Involved
This is the scope of house extensions on a project in Fleet. What differs between one job and the next is the building, not the service.
Planning Advice and Drawings
Existing and proposed drawings prepared to the standard the local authority expects, with advice on whether permitted development is even in play.
Existing Opening Assessment
Where the extension joins the existing house, the load path through that junction is designed rather than assumed.
Building Regulation Support
The technical detail behind the drawings, from insulation and ventilation to structural openings, prepared for building control.
Single and Double Storey Extensions
Layouts worked up around how you actually want to use the space, not around a standard footprint.
The structural question
The Part That Decides the Job
Across Fleet the same issue turns up in both the older stock and the later estates, though for different reasons: one because nothing was recorded, the other because the design assumed nothing would ever be altered.
An extension usually creates the widest structural opening in the house, because the old rear wall becomes an internal opening. That wall is very often load bearing, carrying floor joists, the roof, or both. Sizing the beam means working out what is actually resting on it, allowing for the span, and then checking what the beam bears onto at each end, since a correctly sized beam sitting on inadequate padstones or an unreinforced pier simply moves the problem down the wall.

Questions we get asked
House Extensions in Fleet: Frequently Asked Questions
What does an extension actually cost to design and get approved?
Design, structural calculations and building regulations support are priced against the scope of the project rather than a fixed rate, and we set that out in writing before anything starts.
Do you also work in the areas around Fleet?
Yes. Alongside Fleet we regularly work in Yateley, Hartley Wintney and Farnborough, and across the wider Hampshire border area from our office in Fleet. Bear in mind that some of those neighbouring towns sit under a different council to Fleet, so the planning and building control route can change from one to the next even over a short distance.
Will a project in Fleet need a party wall notice?
Detached and semi detached stock dominates, so many Fleet projects involve one adjoining owner rather than two, and a fair number involve none at all. If the property is semi detached or terraced, or if the foundations for any new element sit close to a boundary, the Party Wall etc. Act 1996 is likely to apply and notice has to be served before work starts. We can confirm the position once we have seen the property, and serve the notices as part of the same project rather than leaving you to arrange it separately.
Are there heritage or planning constraints to watch in Fleet?
Yes. Hart applies tight controls around the Fleet Pond Site of Special Scientific Interest, and the Thames Basin Heaths Special Protection Area sits close by, both of which can matter where a project creates additional dwelling space rather than simply reorganising it. Where any of that applies to a property, permitted development cannot be assumed, and on a listed building even internal alterations can need consent. We establish which of these apply to your address at the start, because it can change the structural solution as well as the paperwork.
Will removing the old rear wall need a steel beam?
Usually, if that wall carries load. The size depends on the span, what sits above it, and whether a flat or pitched roof loads it. In some cases a proprietary lintel is sufficient, but the calculation is what decides that, not the appearance of the wall.
Does the ground in Fleet affect the foundation design?
It can. Across Fleet the underlying ground is commonly London Clay with overlying Bagshot sands, so the ground can change noticeably over a short distance, and that has a bearing on foundation depth, on how a new bearing is detailed, and on how close to mature trees a foundation can sensibly go. That is a general description of the area rather than a statement about any particular plot, so where foundations are involved we design against what an investigation on the site actually shows.
How long does an extension project take from first contact to approval?
The design and structural work is usually the quicker part. The variable is the approval route, since a full planning application runs to a statutory determination period while a permitted development scheme can move straight to building regulations.
Do I need building regulations approval even if I do not need planning permission?
Yes. Planning permission and building regulations are two separate systems. An extension that is entirely permitted development still needs building regulations approval, and that is where the structural calculations, insulation, ventilation and fire safety detail are assessed.
Do you cover the whole of Fleet, including Fleet Pond?
Yes. Fleet is fully within our normal working area for house extensions, from Fleet Pond, Fleet Road, Elvetham Heath and Ancells Farm through to the surrounding streets. This is our own doorstep, since the office is on Reading Road South, so a Fleet site visit is usually the easiest one in the diary to arrange at short notice.
Which council handles building control for house extensions in Fleet?
Fleet falls under Hart District Council. It is the local planning authority, with Hampshire County Council above it for highways matters such as skip permits and any scaffold that reaches the pavement. That matters because a set of calculations and drawings has to be submitted to the authority that actually covers the address, and on this patch the boundaries run close together, so neighbouring towns can sit with entirely different councils.
Nearby and related
More Around Fleet
House Extensions near Fleet
Our other services in Fleet
Talk it through first
House Extensions in Fleet
Tell us what you are trying to do with the space and we will tell you what it involves. We are based at First Floor, 30 Reading Road South, Fleet, and Fleet is well within our normal working area. Every project gets a written scope and price after we have seen the property.
