A new roof is one of the most significant investments you will make in your home, and getting the process right from the first inspection to the final clear-up makes the difference between a job that lasts decades and one that causes problems within years.
A new roof is not simply a case of lifting old tiles and laying new ones. The structure underneath, the materials you choose, the way the details are finished at the edges, valleys and chimney flashings, and the quality of the underlays and battens all determine how long the finished roof performs. Understanding each stage helps you ask the right questions and spot whether a contractor is cutting corners.
At Dereham Roofers we install new roofs for homeowners in Necton and across mid-Norfolk, using materials suited to local conditions. This page walks you through the full process so you know exactly what a properly done job looks like, from the moment we first look at your roof to the moment we leave your property clean and tidy.
Before any work is priced or planned, a thorough inspection is essential. This means getting up onto the roof, not just looking at it from the street. A close inspection will check the condition of the existing timbers, the rafters and ceiling joists, the ridge board and any purlins that carry the main load. It will also look at the condition of the current underfelt or sarking, the state of the battens, and whether the existing ventilation is adequate.
In older properties, the timbers are often sound but the underfelt has become brittle with age. In some cases, particularly where a previous roof was laid without proper ventilation, there can be dampness in the rafters or early signs of rot at the eaves. A good inspection identifies all of this before a price is agreed, not after work has started.
You should expect any contractor to explain what they have found in plain terms. If a surveyor or roofer tells you the timbers are fine without having actually accessed the loft and roof space, that is a warning sign. Timber problems found mid-job can significantly increase the final cost if they were not identified upfront.
Keep any prices you see in perspective: they vary with the size of the roof, its pitch, the number of hips and valleys, chimney flashings, any dormer windows and what the existing structure requires. A simple gable-to-gable roof costs significantly less than a hipped roof of the same floor area.
Every new roof on a two-storey or steeply pitched single-storey property should be done from proper scaffold. A scaffold tower or ladders alone are not suitable for stripping and re-roofing. Full scaffold around the perimeter allows materials to be stored safely at eaves level, reduces the risk of tiles or debris falling, and lets the roofers work efficiently without repeatedly climbing up and down.
Scaffold hire is a genuine cost that should be included in any quotation. If a price seems unusually low, check whether scaffold is included. A typical scaffold for a semi-detached house will add £600 to £1,200 to the job, sometimes more for larger or more complex properties. It is money well spent for safety and for the quality of the work.
Before stripping starts, waste skips or bags should be organised. A full roof strip generates a significant amount of waste. Old tiles, broken slates, degraded underfelt and rotten battens all need to be removed and disposed of properly. This should be factored into the quote, and you should ask where the waste goes.
Stripping is the removal of all the old tile or slate coverings, the battens and the old underfelt. On a full re-roof, everything comes off down to the bare rafters. This is the stage at which the true condition of the timbers becomes clear.
A common problem on roofs that are 40 or more years old is that the underfelt has become completely degraded. Old black bitumen felt goes brittle and can tear at a touch. It will no longer hold back wind-driven rain or debris. Some older roofs, particularly those laid before felt became standard, have no underfelt at all. In both cases, the new installation must include a modern breathable membrane.
During stripping, any timber that shows signs of rot, insect damage or significant deterioration should be cut out and replaced. Rafters that have sagged or split need to be sistered with new timber alongside them. Ridge boards and purlins should be checked. This is not an optional extra; it is part of doing the job properly. You should expect this to be discussed openly and priced separately if it is needed, not hidden in a later bill.
Once the roof is stripped, any structural repairs are carried out before new materials go on. This might include replacing individual rafters or sections of rafter, re-fixing a purlin that has pulled away from a wall, or adding extra noggings and supports at the eaves where the original timber has deteriorated.
In some older properties, the rafters are undersized by modern standards. Adding insulation between and below rafters as part of a re-roof is an opportunity to bring the roof up to a better thermal standard. Building regulations now set minimum insulation levels for re-roofing work. The requirement in England is typically a U-value of 0.18 W/m2K for the roof as a whole, though the exact approach depends on whether the loft is used as habitable space or left as a cold loft. A contractor should be able to explain what is needed for your specific situation.
Once the timbers are sound, the new breathable membrane goes on. This is laid from the eaves upward, lapped correctly at every join, and dressed into the gutters at the bottom so that any water that finds its way under the tiles is carried to the gutters rather than into the roof space. Getting this detail right at the eaves matters. Underfelt that is cut too short, or that sags and forms a pocket rather than draining cleanly, is a common cause of water ingress even on otherwise well-laid roofs.
New treated timber battens are then fixed through the membrane into the rafters. The gauge of the battens, meaning the spacing between each one, is determined by the tile or slate being used and the pitch of the roof. Each manufacturer specifies the correct gauge for their product at different pitches. Laying battens at the wrong gauge causes tiles to sit incorrectly, can crack them under load, and can allow wind and rain penetration. A roofer who measures and marks the batten gauge properly is doing the job as it should be done.
Tiles or slates are fixed from the eaves upward. The eaves course is doubled up to close the gap at the bottom of the roof. On concrete interlocking tiles, most of the fixing is done by the interlocking design itself, with additional nails or clips at exposed areas such as verges, eaves, ridges and any tiles adjacent to hips or valleys. On plain clay tiles and natural slate, individual nailing is the standard method.
Valleys, where two roof slopes meet in a channel, can be formed using lead-lined valley troughs, dry-cut valley systems or open lead valleys. Lead valleys, when properly fitted with correctly sized lead in the appropriate code weight, are the most durable option and will outlast the tiles around them. Hip and ridge tiles are bedded and pointed in mortar, or in modern systems fixed with a dry-ridge system that avoids the need for wet mortar and reduces the risk of future cracking and slipping.
All chimney flashings are formed in lead. Code 4 lead is the minimum for soakers and step flashings against a chimney stack or a parapet wall. The lead should be dressed correctly into the mortar joints of the brickwork and fixed with lead tacks and wedges, then pointed over with an appropriate mortar. A flashing that has simply been stuck on with mastic or lap tape is not a proper repair and will not last.
Roof ventilation is often overlooked but is critical to the longevity of both the roof timbers and the insulation below. Building regulations require ventilation equivalent to a continuous 25mm gap at the eaves for cold loft construction, or cross-ventilation at high and low levels for warm roof construction where insulation is between and above the rafters.
Breathable membranes reduce but do not eliminate the need for eaves ventilation. In-line ventilator tiles can be added to the main roof covering to supplement ventilation where the design requires it. A roof that traps moisture in the timbers will show signs of condensation, dampness and eventually decay, even if the tile covering itself is sound.
A re-roof is a natural point at which to review the condition of your guttering, fascias and soffits. The scaffold is already in place, which makes any work at eaves level significantly easier and cheaper than returning with fresh scaffold later.
Original timber fascias on older homes frequently show signs of rot, paint failure or fixing failure by the time the roof needs replacing. Upcycled or replacement uPVC fascias and soffits are a straightforward upgrade that removes the need for painting and provides a cleaner finish for the new guttering to fix to. New guttering should be checked for correct fall toward the downpipe outlets. Gutters with zero or reverse fall hold standing water, which breeds algae and eventually causes the gutter joints to leak.
Once the roof covering is complete, the ridge and hip tiles are finished, the flashings are pointed and the verges are secured, a final inspection should be carried out. This means walking the roof to check that no tiles have been left un-clipped at vulnerable points, that no mortar joints are hollow or unfinished, and that the gutters are clear of debris from the laying process.
Scaffold is then struck and the ground around your property is cleared. Old materials removed during the strip should already have been taken away in skips or bags during the job; any remainder goes at this stage. The finished job should leave no nails, broken tiles, offcuts of lead or mortar debris on your property.
It is worth carrying out a check yourself once the scaffold is down and the roofer has signed off. Walk around the property and look along the roofline from the ground. Check that ridge tiles sit level and that mortar pointing looks consistent. Check inside the loft on the first wet and windy day after the roof is finished to confirm there is no dripping or damp patches on the new membrane.
A new concrete tile roof, properly laid on sound timbers with good ventilation, should give 40 to 60 years of service. Clay plain tiles last longer, often 60 to 100 years or more. Natural slate, if the quality is good and the fixings are correct, can last well over a century. The weakest points in any roof are the mortar details at ridge, hips and chimney flashings, which typically need attention after 15 to 25 years regardless of the tile type.
Lead flashings, when properly installed in the correct code weight, will outlast most tile coverings. Replacing flashings with lead at the time of re-roofing is always worthwhile.
Asking these questions before work starts puts you in a much stronger position if any disagreement arises during the job. A contractor who cannot or will not answer them clearly is worth reconsidering.
Dereham Roofers carries out new roof installations for homeowners in Necton and across mid-Norfolk. If your roof is showing signs of age, persistent leaks, or you are planning to replace it as part of a wider renovation, it is worth arranging a roof survey and asking for a clear, itemised quote. We will come out, get up on the roof and give you an honest assessment of what the job actually involves before any price is agreed.
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Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
