Design, Calculations and Building Control
House Extensions in Farnham
Farnham sits under Waverley Borough Council, and that is the authority whose building control team will sign off the structural work on your project. Open Plan Homes Limited provides house extensions across Farnham and the surrounding Surrey border area, with the drawings, calculations and paperwork prepared for the authority that actually covers your address rather than a neighbouring one.
Every enquiry starts the same way: we look at the property, establish what is genuinely load bearing, and then set out in writing what the work involves and what it will cost. Nothing is priced from a photograph.
Farnham, Surrey
Local Considerations for House Extensions in Farnham
- Planning authority
- Waverley Borough Council
- County
- Surrey
- Typical ground
- Folkestone Formation greensand with river terrace deposits along the Wey valley
- Party wall exposure
- Terraced and semi detached property is common right through the older centre, so party wall notices are part of most projects rather than an exception.
Farnham covers a real mix of building stock, and which part of the town a property sits in changes what house extensions actually involves. Around Castle Street, Gostrey Meadow and the Bourne, the older stock is Georgian brick townhouses along Castle Street, West Street and Downing Street, with Victorian terraces behind East Street. Further out you find post war and later estates out toward Weybourne, Badshot Lea and Rowledge, where the construction is more standardised and the structural picture is usually easier to establish.
On the planning side, Waverley Borough Council is the local planning authority, with Surrey County Council above it for highways matters such as skip permits and any scaffold that reaches the pavement. It is also worth knowing that Farnham has one of the largest conservation areas in Surrey, covering most of the historic town centre, and a number of the Georgian frontages are listed in their own right. None of that necessarily stops a project, but it does change the route, and it is far cheaper to establish before a design is fixed than after.
The ground under Farnham is commonly Folkestone Formation greensand with river terrace deposits along the Wey valley, which is relevant wherever a foundation or a new bearing is involved, though a site investigation is what confirms it for a particular plot. Terraced and semi detached property is common right through the older centre, so party wall notices are part of most projects rather than an exception. Castle Street and the streets running off it are narrow and often restricted for loading, so on town centre projects the practical questions about skip permits, scaffold licences and delivery windows come up early rather than at the last minute.
What is included
House Extensions in Farnham: What Is Involved
On a Farnham project, house extensions covers the following. The list does not change from town to town, but what each item involves depends on the property in front of us.
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.
Structural Calculations Included
Beam and lintel design carried out as part of the package rather than sub contracted out and charged separately.
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
In Farnham this comes up most often on Georgian brick townhouses along Castle Street, West Street and Downing Street, with Victorian terraces behind East Street, where the original construction was never drawn and has to be established on site.
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 Farnham: Frequently Asked Questions
Does the ground in Farnham affect the foundation design?
It can. Across Farnham the underlying ground is commonly Folkestone Formation greensand with river terrace deposits along the Wey valley, 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.
Can you work with drawings an architect has already produced?
Yes. If the design work is done, we can pick up the structural calculations and the building regulations detail from the existing drawings, provided the drawings reflect what is actually on site.
Which council handles building control for house extensions in Farnham?
Farnham falls under Waverley Borough Council. It is the local planning authority, with Surrey 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.
Will a project in Farnham need a party wall notice?
Terraced and semi detached property is common right through the older centre, so party wall notices are part of most projects rather than an exception. 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.
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.
Are there heritage or planning constraints to watch in Farnham?
Yes. Farnham has one of the largest conservation areas in Surrey, covering most of the historic town centre, and a number of the Georgian frontages are listed in their own right. 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.
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 Farnham?
Yes. Alongside Farnham we regularly work in Aldershot, Farnborough and Fleet, and across the wider Surrey border area from our office in Fleet. Bear in mind that some of those neighbouring towns sit under a different council to Farnham, so the planning and building control route can change from one to the next even over a short distance.
Do you cover the whole of Farnham, including Castle Street?
Yes. Farnham is fully within our normal working area for house extensions, from Castle Street, Gostrey Meadow, the Bourne and Upper Hale through to the surrounding streets. Castle Street and the streets running off it are narrow and often restricted for loading, so on town centre projects the practical questions about skip permits, scaffold licences and delivery windows come up early rather than at the last minute.
What is a party wall notice and will my extension need one?
If you are building on or up to the boundary, excavating near a neighbour's foundations, or cutting into a shared wall, the Party Wall etc. Act 1996 applies and notice has to be served. Extensions on a semi detached or terraced property very often trigger it.
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House Extensions near Farnham
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Talk it through first
House Extensions in Farnham
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 Farnham is well within our normal working area. Every project gets a written scope and price after we have seen the property.