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Daylight passing through a wall of fluted translucent panels, graded from sea-glass green through aqua and periwinkle to violet, with the shadows of the structure cast across the ribs.

Building problems

Something is wrong with the roof. Start with what you can see.

Water on the floor on a dry morning. A building that will not hold its heat. A roof that rusts, drums in the rain or bakes the floor in July. Twelve problems, each with its own page: what you are seeing, what is causing it, what it is costing you, and what actually fixes it. No product talk until the problem has a name.

Find your problem
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01Water, damp and the fabric of the roof

Six problems that start with water, and the roof that carries it.

Two of these are regularly mistaken for each other, so the first page tells them apart. Each of the others starts from what you can see from the floor and ends with what fixes it, with the facts and their limits written beside them.

Looking up at the underside of a profiled steel roof on a wet, cold morning: a fine mist of condensation across the whole sheet, and separately one lap beside a rooflight with a dark stain and a heavier wet run.Diagnose firstCondensation, or a roof leak?Water is coming from the roof and it is not obvious why. Three observations separate the two, and the answer changes who you call.Tell them apart Looking up at the underside of a profiled steel roof on a cold morning: fine, even condensation across the whole sheet between the purlins, under a rooflight.Metal and fibre-cement roofsRoof condensationWhy a sound roof rains inside on a clear, cold morning, what the water ruins, why fans and dehumidifiers rarely cure it, and what does.Read the problem Dark mould spreading across a stained ceiling liner beneath a metal roof, in the pale light of a working building.Floors, liners, stockDamp and mouldDrips that land in the same places every winter leave wet floors, stained liners and mould. Where the moisture comes from, and how it stops.Read the problem Rust streaks running from the fixings down the underside of a profiled steel roof sheet, seen from below.Fixings and purlins firstCorrosion of metal roofsA sheet that is wet from beneath every cold morning rusts from beneath. What a dry underside does for the life of the roof.Read the problem An old corrugated asbestos-cement roof on a UK industrial building, weathered and marked with lichen, under a grey sky turning pale.The roof stays in placeFibre-cement and asbestos-cement roofsBrittle, cold, and expensive to take down. How the underside is insulated and encapsulated while the roof stays exactly where it is.Read the problem An ageing profiled roof over a UK industrial unit, its sheets faded and patched, seen across the roofline in soft daylight.Before replacementAgeing and failing roofsThinning sheets, failing fixings and a replacement quote nobody wants. What a bonded layer from below can and cannot do for an old roof.Read the problem

Not sure which one you have? Two photographs of the underside usually settle it, and a specialist will say which it looks like.Send photographs

02Heat, comfort, cost and compliance

Six problems that start with heat, comfort and the bill.

A bare sheet loses heat in winter, radiates it down in summer, breathes with the wind and drums in the rain. These pages follow each of those to the roof, and on to what a landlord or an owner is asked to meet.

A pale industrial roof interior in which planes of warm violet and aqua light rise through the roof, the heat leaving upward through a bare sheet.Heating, cooling, U-valuesHeat loss and thermal performanceHeat leaves through a bare sheet and out of every lap and fixing; in summer the same sheet heats the floor. What a lower U-value means in practice.Read the problem Hard summer sunlight on a bare metal roof over a UK industrial unit, heat shimmering above the sheet.June to SeptemberSummer overheatingA bare sheet in the sun radiates down onto stock and people. Why the space under the roof overheats, and what an insulated underside changes.Read the problem Daylight showing through the open laps and eaves of a bare profiled metal roof, seen from inside a cold building.Laps, fixings, eavesAir leakage and draughtsOpen laps and fixings breathe with the wind, and no U-value counts that loss. Why a continuous seal matters as much as the depth.Read the problem Heavy rain on a profiled metal roof seen from beneath, the sheet and purlins pale against the wet light.Metal roofsRain noise and acousticsRain on a bare metal roof fills the building with noise. What a bonded layer does to the sheet, and where open-cell foam comes in.Read the problem Translucent glass planes cut at sharp angles cast sea-glass and violet light across pale stone, an abstract HOLVEM composition.The heating billEnergy costsWhere the heating money goes in a single-storey building, why the roof is the first place to look, and what a calculated reduction does and does not tell you.Read the problem Folded pale planes and hard-edged coloured light in the HOLVEM run, an abstract composition for a page about standards and compliance.Landlords and asset managersEPC, MEES and complianceWhat the minimum standards ask of a commercial building, where roof insulation fits, and who determines compliance.Read the problem

03Before anything is specified

The problem is checked before the answer is chosen.

Every one of these problems has been misdiagnosed somewhere: a leak insulated, a condensation roof repaired, a U-value quoted from a product sheet. So the same three steps sit in front of every recommendation HOLVEM makes, whichever door you came through.

  1. Photographs

    From a phone

    The underside on a cold morning, and again during rain, with the same bay in frame. Sent with a postcode, they tell a specialist which problem it looks like and whether a survey is worth your time.

    Survey, or photographs?

  2. Condition survey

    From below

    Substrate, coating, corrosion, moisture, fixings, and whether the roof is letting water in. A leaking roof is repaired first, by a roofing contractor; the layer goes on afterwards, on a sound, dry sheet.

    How a job runs

  3. Condensation risk analysis

    Before the depth

    The build-up is checked for moisture risk to BS EN ISO 13788, and with a dynamic model to BS EN 15026 where the simple method is inconclusive. The U-value is calculated for the roof as it will be built, bridges included.

    Condensation risk analysis

The layer, when it is the answer: closed-cell spray foam from beneath, with the rate falling as the area rises; the cost guide has the figures. A firm price needs the building.Cost guide: rates per m²

Your next step

Your building.
Your brief.
A specialist.

You do not need to know which problem it is. Tell us what you can see, where the building is and what it is used for; if something is uncertain, say so. Someone who does this every day reads it and comes back to you.

Start a project brief About five minutes. Photographs help; nothing else is needed.

Or pick up the phone

Telephone . Before 3pm on a working day, you are contacted the same day. After 3pm, the next working day. A commitment to contact, not a quotation.

Two photographs first? Send photographs of the roof