Building Regulations are the national standards for how buildings are made safe, weathertight and energy efficient. They are separate from planning permission, and the two are often muddled. A re-roof can be free of planning control and still fall inside the Regulations, or the other way round.
The question homeowners ask most is simple: do I need approval for a new roof? Two things decide it: how much of the building is touched, and what the new covering is. Some tile swaps and patch repairs need no application at all. A heavier covering, a renovated flat roof, a loft conversion or a removed chimney breast does.
This guide sets out the Planning Portal's own tests, explains when a roof counts as renovated under Part L, and says who to contact in Test Valley and the neighbouring councils. If you want the planning side, read our planning permission guide. For the whole picture of how we work, start from our Andover roofing page.
The two tests that decide whether you must apply
The Planning Portal gives a clear starting point for a re-roof. Normally no building control application is required where both of these hold: under 25 per cent of the total "building envelope" is touched, and under 50 per cent of the roof is touched. Here the envelope means the whole outer shell of the house: its walls and floor, the roof itself, every window and door, plus any roof windows and rooflights. A roof alone can sit well inside the first test and still fail the second.
Why both figures matter
Read the two limbs together. A re-tile of one slope on a large detached house may touch a small share of the envelope and under half the roof, which is a different situation from stripping the only roof on a small terrace. A one-figure rule of thumb misses the second test, so quote both limbs or neither.
None of the local councils sets a percentage of its own for a re-roof. Basingstoke and Deane's building control page names the work: it counts re-covering pitched and flat roofs as work that "might also need" building control approval. That applies to its own addresses, and the wording is "might", not "always".
What a repair is
Fixing a few slipped tiles, replacing a cracked ridge or re-bedding a flaunching is repair, and sits far below these limits. The tests matter when a whole slope, or the whole roof, is stripped and recovered.
At the survey we work out which side of the line a job falls on and record it in the written price. Keep a note of what you were told. A neighbour's roof done last year without paperwork tells you little about yours, because the tests depend on the size of each house and on what was fitted.
Heavier coverings and different fire performance
Two further triggers apply whatever the area. Approval is also required if the new covering makes the roof 15 per cent or more heavier, or would perform in a fire in a significantly different way to the existing covering. Either is enough alone, even when the area tests above are comfortably met, and a pitched or flat roof makes no difference to that.
The weight test
Approved Document A, the structural guidance, words the limit slightly differently: a significant change in roof loading is an increase of "more than 15%". The Planning Portal says 15 per cent or more. We use the Planning Portal's figure for householders and name it, because the two documents are not identical.
The Planning Portal also advises owners to take advice from a structural engineer or a surveyor before starting. That matters most when you change from one type of tile or slate to another, because the new material can weigh noticeably more than the old. A like-for-like swap on the same battens and rafters leaves the loading alone.
Fixings still count
Approved Document C expects every sheet, tile and section of roof to be fixed in an appropriate manner (para 6.8). A new covering on old, weakened timber is a fixing question as well as a weight question, so a survey looks at the battens and rafters before the covering is chosen.
If a chosen covering fails either test, the job needs approval before the first tile comes off, not after. Building that step into the plan early costs a few days of waiting. Discovering it halfway through can stop a job with the roof open to the weather, which is the worst moment to learn it.
Part L: when a roof counts as renovated
Part L covers the conservation of fuel and power. The relevant guide for homes is Approved Document L Volume 1, whose 2021 edition took effect on 15 June 2022 for use in England. A newer edition, AD L 2026, takes effect on 24 March 2027, so until then the 2021 tables apply and from then the new tables do.
What renovation means
The Building Regulations 2010 define renovation of a thermal element as adding a new layer to it or replacing one of its existing layers. A roof is a thermal element; roof windows and rooflights are not. AD L also classes a fresh flat-roof membrane as renovation, which catches flat roof re-covers that owners often assume are only repairs.
The numbers
For renovated roofs, Table 4.3 sets a threshold U-value of 0.35 and an improved value of 0.16 W/(m2K). Paragraph 4.13 allows a relaxation where upgrading is not feasible technically or in practice, or would fail a 15-year simple payback. A new roof window is held to 1.4 or Band B (Window Energy Rating), and a new rooflight to 2.2. Loft conversions use the renovation figure of 0.16, not the 0.15 that applies to a brand new roof element.
Whether a given re-tile is renovation is a question for your building control body, and the answer depends on what goes in and what comes out. We flag the point in the survey so insulation is never a surprise in the scope. See roof replacement for how a full re-roof is planned around it. Where the survey shows a roof with no insulation worth keeping, the specification and the price say so before work is booked.
Who inspects roof work around Andover
For Andover, Stockbridge, Romsey and the Test Valley villages, the Regulations are administered by your building control body. Test Valley Borough Council plans the area, and it can tell you who handles building control at an Andover address. Do this before the survey date, so the answer shapes the specification instead of arriving after it.
Other councils in our area
Over the border the position differs. Wiltshire Council runs its own Building Control service, and its inspections line is 0300 456 0113. West Berkshire's service is Building Control Solutions, a partnership with Wokingham Borough Council. Basingstoke's own team can be reached on 01256 844844, Winchester City Council runs its own service, and New Forest District Council has a team on 023 8028 5245.
Eastleigh and Southampton share one service, Southampton and Eastleigh Building Control, which Southampton City Council runs with Eastleigh Borough Council.
Private route
You can also appoint a registered building control approver, a private alternative to the council. Registration of approvers began on 6 April 2024, although private building control existed before then. Whichever body you choose, tell your roofer at the survey so the programme can allow for inspection visits.
National park authorities, such as the South Downs and New Forest, deal with planning only. The district or unitary council keeps building control, so a home inside either park still goes to the council for the Regulations.
If you are unsure which council covers your address, check before you phone anyone. Places west of Andover sit close to the Wiltshire border, and the nearest town is not always the council that deals with your property.
Rules that sit beside the Regulations
A roof job can touch several regimes at once, and passing one does not clear the others.
Planning and consent
Under Class C of the permitted development order, a re-roof on a house is normally permitted development, so planning permission is a different question from approval under the Regulations. Flats have no such rights, and a listed home needs listed building consent as well. The planning authority for Andover is Test Valley Borough Council. If the house is listed, ask the council first; our listed building guide explains the route.
Scaffold on the pavement
Scaffold that stands on or over the public highway needs consent from the highway authority under section 169 of the Highways Act 1980. Hampshire County Council holds that role for all seven Hampshire districts, Test Valley among them, and its page states that scaffolders apply for the householder. Scaffold on private land needs no such consent. Ask who is applying, and for how long, when you agree the start date.
Asbestos and waste
An older roof, or the soffits and sheeting around it, may contain asbestos. HSE guidance says to treat a building as containing asbestos if it was built or refurbished before 2000. Weathered asbestos cement can be removed carefully without a licence, but never with a crowbar.
Who carries the duties
Under CDM 2015, where there is a contractor, that contractor picks up the duties that would otherwise sit with a domestic client. If more than one contractor works on the roof, extra duties follow, so ask your roofer who is responsible for what before the first day.
Chimney breasts, loft conversions and conservatory roofs
Some roof-adjacent jobs always sit inside the Regulations, whatever the size.
Taking out a chimney breast
On the Planning Portal's reading, taking out a chimney breast always needs approval, as it forms part of the building's structure. A party wall may be involved too, and that is a separate Act and a separate surveyor. Our chimney repairs hub covers the practical side.
Loft conversions
Approved Document B covers escape from fire. Where a two-storey house gains a loft conversion, the guide expects a protected stair in most cases, though the guide also allows alternatives, including sprinkler protection to the open-plan areas (para 2.23). An escape window needs a minimum openable area of 0.33 square metres, at least 450 mm in height and width, with the bottom of the openable area no more than 1100 mm above the floor. A window counts as an escape route only for storeys no more than 4.5 m up.
A new conservatory roof
On the Planning Portal's reading, a replacement conservatory roof has to meet the Regulations for structural safety, energy efficiency and ventilation. A swap is therefore not a loose repair.
The Part L exemption for a conservatory holds only at ground level, up to 30 square metres in floor area, with separation from the main house, and heat supplied by neither the house system nor a fixed heater. The Building Regulations still apply to a solid replacement roof. Read our choosing a roofer guide if you are weighing who should apply and who should answer for the work. Chimney, loft and conservatory jobs can each bring in building control, which is why they are named here.
