Replacing a roof looks simple from the lane: strip, re-batten, re-cover. The cost and the risk sit in what the old roof is hiding. Rafters may have rotted at their feet, battens may have failed, a chimney may need work before the new covering goes round it, and the slope may need a scaffold that has to be built on a bank. None of that is visible on a quick look from the road.
A scoping survey is the visit that brings all of it into view before a price is fixed. That separates it from a first quote visit or a general condition check. It is the survey that turns a decision to replace into a defined job: which timbers stay, which coverings can be reused, which paperwork applies, and how people and materials reach the roof. This guide covers that visit. For how a survey differs from a quote visit, see survey or quote visit. The wider service sits on our roof inspections and surveys page.
What a scoping survey is for
The purpose is to remove surprises. A quote written from the ground has to guess at the timber, the underlay, the condition of the chimney and the access, and a guess either costs too much or turns into extras once the roof is open. A scoping survey replaces the guess with a record.
What it settles
By the end of the visit we should be able to say what the roof is made of, how it is built and how it is failing. We should also be able to say whether replacement is the right answer at all, since a roof with a localised fault may need a repair and not a new covering. If the job is a re-roof, the survey fixes the scope in writing: the area to be stripped, the structural repairs to expect, the details to be renewed, the paperwork to be done and the access to be built.
What it does not settle
It cannot see every timber. Boarding, plastered ceilings and fixed insulation hide parts of the frame, and some defects only appear once the covering is off. A good survey names the areas it could not see and allows sensibly for them, so an unexpected rafter repair is a known possibility. Our guide to what a roof survey covers sets out the usual scope and its limits.
Structure first: rafters, battens, wall plates and the frame
The covering is replaceable. The frame under it is what the new roof has to rest on, so the survey starts there, from the loft. We check rafters along their length and at the bottom end, over the wall plate, where water from a failing eaves tends to collect. We check purlins, hangers and ties for sag, splits and loose joints. We press on timber to test for softness, and we look for the staining, frass and flight holes that mean rot or beetle.
Deflection and ponding
Sighting along ridge, eaves and slopes shows whether the roof has sagged or spread. A dip that has stayed constant for years may be harmless. A dip that is new, or a crack in the wall beside it, needs more thought. On a flat roof, deflection leads to ponding, standing water that adds weight and shortens the life of the covering. BS 6229 guidance, as set out by IKO and Rockwool, designs for 1:40 to leave a finished 1:80, and we measure what your roof actually has.
Battens, boarding and underlay
Battens are checked for rot and for the nail damage that tells us whether the covering has been slipping. On older roofs we note whether there is sarking board or felt, in what condition, and whether the underlay would need replacing. Most re-roofs renew battens and underlay together with the covering, since reusing old ones puts a new roof on a tired base.
Where a structural fault is found, the quote covers the repair: sistering a rafter, replacing a wall plate, renewing a section of purlin. Photographs from the loft show you the same timber we see.
Which coverings can be reused
Whether the existing material can go back on the new roof decides much of the cost, and it depends on the covering. The survey sorts it into three groups.
Slate and stone
Natural slate and stone slate can be reused if they are sound. A slate that rings clean when tapped and has intact peg or nail holes is a candidate for reuse; one that is flaking, split or with a worn hole is not. On a stone roof, Cotswold District Council's 2000 guidance records about 50% perished as common on a stripped stone roof, so the survey allows for a share of new stone. The English Heritage policy it reprints favours fresh quarried stone, and says salvaged slates belong only on their original building.
Clay and concrete tiles
Clay tiles can often be reclaimed if sound. Concrete tiles are less likely to be reused, since they lose surface texture and are heavy to handle. Interlocking tiles that are discontinued may be impossible to match, which affects whether a repair or a full replacement is the sensible route.
Ridge, hip and lead
Ridge and hip pieces are usually renewed. Under BS 5534:2014 the new ridge is fixed mechanically as well as bedded, either with dry-fix systems tested to BS 8612 or with clips and bedding together. Lead flashings are checked for splits and thinning. Old lead is often renewed, as new code lead is a small cost against the risk of leaking round a chimney in a new roof.
The quote lists what is reused and what is new, so you can see how the saving arises.
Building control triggers: when the paperwork starts
The survey also settles whether Building Regulations apply. Replacing a roof covering like for like does not always need approval, but several triggers can bring it in.
The thresholds
Under the Planning Portal's guidance, a building control application is not normally needed where under 25 per cent of the building envelope and under 50 per cent of the roof is touched by the work. A whole-roof replacement usually goes past the second figure, so approval normally applies. It also says approval is needed if structural alterations are made, if the new covering resists fire in a notably different way, or if the new covering increases the roof's weight by 15 per cent or more. For the weight rule, Approved Document A gives a similar test, with the wording "more than 15%". Where the two differ, building control has the final say.
Thermal upgrade
Approved Document L (2021) requires the entire roof to reach a stated U-value when more than 50% of its surface is renovated, or the scheme is classed as major renovation. Where the roof is stripped to expose the rafters and rebuilt, that can mean adding insulation, which affects depth, eaves details and cost.
Who handles it
Building control comes from the council or a registered building control approver. In Stroud District that means the Gloucestershire Building Control Partnership, shared with Gloucester City. We explain which rules reach your roof and see to the paperwork wherever it applies. A listed building or a conservation area adds planning questions that sit with the council's planning team, which we recommend you check before the work is booked.
Access, scaffold and the shape of the site
Many roofs in the Five Valleys sit on a slope, up a narrow lane or behind terraces, and the survey records how scaffold, skip and materials will physically get to the house. This is where a quote gets honest. A scaffold on a flat drive is a day's job. One on a steep bank, or across a neighbour's land, can be a different order of cost.
What we measure and ask
We note the height of the eaves, the ground at the foot of each elevation, whether the scaffold can stand square, and whether the pavement or a neighbour's property is involved. We check where the skip and the materials lorry can stand, and whether tiles must be hand-carried, hoisted or craned. We ask about parking, overhead cables and trees. Our guide to roof survey cost explains what drives the price of the survey itself.
Cost context
MyBuilder's 2026 new roof cost guide has scaffolding for a re-roof near £1,125 and waste disposal at £100 to £1,000, as national figures. Checkatrade's October 2026 guide gives scaffold at £700 to £1,300. Those are ranges. What you pay depends on the house and the site, so we measure on the day and include the scaffold in the written quote.
Ground conditions, neighbours and the waste route go into the plan before the scaffold arrives.
Chimneys, roof windows, vents and the details around the edge
A new roof is only as good as the details it is built around, and the survey lists every one. Chimney stacks are checked for crumbling pointing, cracked flaunching, leaning and loose pots, because the new flashings need something sound to fix to. A stack that needs rebuilding is better dealt with before the covering goes on, with scaffold already up.
Roof windows and rooflights
Existing roof windows are checked for leaks at the flashing, condition of the frame and age. A re-roof is a sensible moment to replace an ageing one, because a second scaffold later would cost more. New units must meet Approved Document L, which sets roof windows at 1.4 W/m²K (or Window Energy Rating Band B) and rooflights at 2.2 W/m²K.
Ventilation and the roof space
We look at how the roof breathes. Cold-roof ventilation under BS 5250 turns on the underlay type and the pitch, so the survey notes eaves vents blocked by insulation, existing ridge vents and any signs of condensation. A new underlay can change the ventilation needed, so the specification is set at survey stage.
Other points
We note fascias, soffits, bargeboards and gutters, since these are accessed once the scaffold is in place. We also record anything suspect, such as asbestos cement sheeting or old spray foam, because HSE guidance sets conditions for handling the first. Protected bats and nesting birds are reported before work starts.
From survey to written quote
The survey ends with a written report and a quote based on it. The report describes the roof as we found it, illustrated with your own roof's loft, slopes and details. The quote covers the whole job: scaffold, strip, structural repairs, battens and underlay, covering, ridge and hip, lead, chimney work, making good, waste and VAT.
Reading the quote
Where the survey could not see something, the quote flags it and carries a provisional allowance for what the open roof might reveal. Where the covering is being reused, the quote shows the quantity of new material still needed. Where Building Regulations apply, the quote says who does the application and what inspections follow.
Comparing quotes
If you hold other quotes, compare what each one covers as well as the total. A lower price that says nothing about scaffold, timber or building control is not a like-for-like comparison. Ours is built to be compared.
Typical national costs are worth knowing in advance. MyBuilder's 2026 guide gives £5,000 to £12,000 for a full re-roof, with gable roofs £5,000 to £8,000 and hipped roofs £8,000 to £12,000, and Checkatrade's October 2026 guide puts most re-roofs at £4,000 to £19,000. The figure for your roof comes only after the survey.
Our workmanship guarantee runs for 10 years, in writing, and waste leaves with us.