A pitched roof with roof tiles is the most familiar type of roof in the Netherlands, and it lasts a long time as long as it is properly maintained. Yet there comes a point when putting a loose tile back is no longer enough: the tiling battens have gone soft, the underlay is worn out or you finally want to insulate the roof properly. This article explains how to recognise the signs, when a repair is enough and when the tiles come off, how to insulate, which rules apply and what a roofer does. If you have a flat roof, read Replacing a flat roof. If there is water in your attic right now, start with A leak: which tradesperson do you call?
Signs that your tiled roof needs attention
You do not need to climb onto the roof to see a lot. Look from the street or the garden, with binoculars if necessary, and look at the inside of the roof from the attic. Watch out for these signs:
- Slipped or broken tiles. Storms, frost or someone who has walked across the roof can cause tiles to slip or break. Rain and driving snow get under the tiles through the gap.
- Loose ridge tiles and a sagging ridge. The ridge tiles are the tiles on the ridge. If they were bedded in mortar, that mortar can crack and come loose over time. A ridge that visibly sags may indicate a problem in the load-bearing structure; have that assessed.
- Moss and deposits. Moss retains moisture and washes into the gutter when it rains, where it causes blockages. Do not have the roof cleaned with a pressure washer: that can damage the surface of the tiles and blow water under the tiles.
- Rotten tiling battens or counter-battens. Tiles that start to sag or keep slipping, and battens that are visible from the attic and feel soft or are discoloured, can indicate wood rot.
- A weathered underlay. If from the attic you can see daylight between the tiles, tears or holes in the membrane under the tiles, or dark moisture marks on the roof boarding, the underlay is no longer protecting the roof properly.
- Lead and zinc work. There is lead or zinc around the chimney, a dormer and in the valley gutter. Loose lead flashings and cracked zinc are a common source of leaks.
- Damp patches inside. Wet insulation or mould on the roof boarding is the clearest, and often the last, sign.
Moss that washes off the roof ends up in the gutter. How to deal with a blocked gutter is explained in Cleaning or replacing a gutter.
How a tiled roof is built up
From inside to outside, a traditional tiled roof usually consists of the rafters or purlins that carry the roof, the roof boarding of timber boards or sheet material, and on top of that a waterproof membrane or underlay. On the boarding are the counter-battens, battens that run from the ridge to the gutter, and over them the horizontal tiling battens on which the tiles hang. The counter-battens create space under the tiling battens, so that water that gets under the tiles can drain away to the gutter and air can flow. In older homes the roof boarding is sometimes missing and the tiles hang on battens with only a membrane, or even nothing, underneath.
Repair or renovate the whole roof?
Not every problem means a new roof. A roofer can usually repair a few broken tiles, a loose ridge tile or a leaking lead flashing locally. If your type of tile is no longer available, they will look for a second-hand tile or a matching model.
Renovation is called for when the problems are no longer local: many porous or broken tiles, rotten tiling battens in several places, an underlay that is worn out across the whole roof surface, or the wish to insulate the roof from the outside. A full renovation goes roughly like this:
- the tiles come off and, if they are still in good condition, are set aside to be relaid;
- the old tiling battens, counter-battens and underlay are removed;
- the roof boarding is checked and repaired or replaced where necessary;
- insulation may be added, with a new vapour-permeable, waterproof layer;
- new counter-battens and tiling battens are fitted;
- the old or new tiles go back on, with new ridge tiles on the ridge and renewed lead and zinc work;
- the connection to the gutter is adapted to the new roof build-up.
Whether you can relay the old tiles depends on their condition; when taking them off, a roofer can assess which ones are still usable. A fixed lifespan for tiles, battens or underlay cannot be given: it depends on the material, the location, the workmanship and the maintenance. Let the condition of the roof guide you.
Insulating: from outside during the renovation or from inside
If the tiles are coming off anyway, that is the moment to insulate. There are two routes.
- From outside. The tiles come off, insulation boards go onto the roof boarding or the rafters, and then come new counter-battens, tiling battens and the tiles. According to Milieu Centraal (the Dutch environmental information centre), this method is particularly suitable if you are going to renew the roof anyway, it is always work for a professional, and the roof becomes higher, so the connection to the gutter has to be redone too. The advantages are a continuous insulation layer and keeping the space in the attic.
- From inside. Insulation goes against the inside of the roof or between the rafters, finished with a vapour control layer and a board finish. This can be done separately from a roof renovation and involves no work on the tiles, but it costs some height in the attic. With a roof that has a poor underlay or rotten battens, internal insulation does not solve that problem.
If you also want more space in the attic, a renovation can be combined with fitting a dormer. That has its own rules, including for insulation: the new-build values apply to a new dormer (Article 5.20, paragraph 3, Bbl); see Fitting a dormer: permit-free or permit required?
Vapour control, vapour-permeable layers and roof ventilation
When insulating, a lot revolves around moisture. In a home, the air contains water vapour that wants to escape outside through the structure. The principle is therefore a vapour control layer on the warm side, the inside, and a vapour-permeable but waterproof layer on the cold side, under the tiles. Any moisture that does get into the structure can then escape outside. If the tight layer is on the wrong side, or timber is enclosed between two vapour control layers, the timber can become too damp and start to rot. Junctions at walls, the ridge, roof windows and penetrations must be carefully taped; a gap in the vapour control layer lets humid air into the structure at precisely one spot.
The space under the tiles must also be able to ventilate. Air flows in under the tiles at the gutter and out again at the ridge, so that moisture is carried away. At the foot of the roof there should be a provision that keeps birds and vermin out without blocking the airflow, often called a bird comb (vogelschroot).
And inside? A better insulated and more airtight home still needs fresh air. Milieu Centraal stresses that the supply of fresh air and the extraction of stale air must continue day and night. So after insulating, check that your ventilation is in order.
What does the Bbl require, and which subsidy and VAT apply?
For insulation during renovation, the Besluit bouwwerken leefomgeving (Bbl, the Dutch Building Decree) applies. The principle when renovating is the rechtens verkregen niveau (legally acquired level): the quality after the renovation must not be lower than before. For insulation this has been tightened. When renewing or replacing insulation layers, a roof must have a thermal resistance (Rc) of at least 2.1 m²·K/W, or the legally acquired level if that is higher.
The higher new-build value does not apply to an ordinary roof renovation. It does apply to a major renovation: when more than 25 per cent of the total building envelope (roof, façades and floor together) is completely renewed, including all layers. The new-build value then applies to the renewed parts, which for a roof of a home is Rc 6.3 m²·K/W. If the roof boarding of a tiled roof stays in place, there is no question of a major renovation. If the boarding is also renewed on a home with a large roof surface, have it calculated whether the threshold is exceeded.
For roof insulation, as an owner-occupier, meaning an owner who lives in the home themselves, you may qualify for the ISDE, the national subsidy administered by RVO (the Netherlands Enterprise Agency). The main conditions: it concerns insulating the existing roof, the newly installed insulation material has an Rd value of at least 3.5 m²·K/W, the insulated area of the roof and any attic or loft floor together is at least 20 m², a company carries out the work in full and the home was built before 1 January 2019. Insulation that is already in the roof does not count towards the required Rd value. A roof and attic floor above each other in the same space only qualify for a subsidy for one of the two. You apply for the subsidy after the work has been carried out, within 24 months. Check the current conditions on rvo.nl before you commission the work; you can read more about the scheme in Sustainable renovation: subsidies and options.
As for VAT: labour for installing insulation in a home that is more than two years old falls under the reduced rate of 9%; the insulation materials themselves and the other roofing work, such as replacing tiles and battens, fall under 21%. So with a renovation in which the tiles are also replaced, 9% applies only to the hours spent on insulating. More on this in 9% or 21% VAT on renovations.
Asbestos, birds and solar panels: think ahead
Asbestos. In homes from before 1994 there may be asbestos in the roof, for example in asbestos-cement roof slates, in corrugated sheets on an extension or shed, and in roof boarding or sheet material under the tiles. Whether that is the case can only be established by an inspection by a certified company. How that works and what you are allowed to do yourself is explained in Recognising asbestos when renovating.
Birds. Birds like to nest under roof tiles. Nests of wild birds are protected by law (Article 11.37 Besluit activiteiten leefomgeving, the Dutch Environmental Activities Decree). For most species that protection applies while the nest is in use, but the permanent nesting sites of species including the house sparrow and the swift are protected all year round, and it is precisely those species that like to nest under roof tiles. So before the renovation, have it checked whether there are nests, plan the work outside the breeding season if possible, and if you are unsure about the species or if a nest is occupied, call in an ecological expert first. Bats can also roost under the tiles or behind the roof boarding, and they are protected too. If the work affects protected animals or their nests or roosts, an omgevingsvergunning (environmental permit) for a flora and fauna activity may be required (for bats under Article 11.46 Besluit activiteiten leefomgeving), which you apply for via the Omgevingsloket (the national online permit portal); in a number of provinces and municipalities there is a scheme for nature-friendly insulation under which the work must be reported in advance. Your roofer or the omgevingsdienst (regional environmental service) knows which approach applies in your province.
Solar panels. If you want solar panels, have the roof renovated first and install the panels afterwards. If they go on a roof that is due for replacement in the foreseeable future, they will have to come off again later. During a renovation the tiles are off anyway, so the fixings and cable entry can be properly prepared. More on this in Having solar panels installed.
Permits and listed buildings
Replacing roof tiles is ordinary maintenance. For an ordinary home you do not need an omgevingsvergunning (environmental permit) for this, as long as the detailing, profile and design of the building do not change (Article 2.29, under a, Bbl). For the technical part, the load-bearing structure must not change. If you choose a tile with a different profile or a clearly different appearance, or if the roof becomes visibly higher because of a thick insulation package, it may no longer count as ordinary maintenance and your municipality's omgevingsplan (environment plan) determines whether you need a permit, especially on the street side. If in doubt, do the permit check in the Omgevingsloket or ask the municipality; more on this in When do you need a permit?
With a rijksmonument (national listed building), the only work that is permit-free is necessary regular maintenance aimed at preserving the heritage values, as long as detailing, profile, design, type of material and colour do not change, and an internal change to a part of the monument that has no heritage value (Article 13.11 Besluit activiteiten leefomgeving). Different tiles, a different colour or external insulation that changes the appearance therefore require a permit for a national listed building. For municipal listed buildings the rules are set out in the omgevingsplan or the heritage bylaw, and in a protected townscape or village view additional rules may apply.
Safety: scaffolding, fall protection and the gutter
Working on a pitched roof is working at height. The Arbobesluit (Dutch Working Conditions Decree) requires employers, and for these rules self-employed people without staff too, to take measures against the risk of falling. According to the Arbobesluit, with a potential fall height of 2.5 metres or more there is in any case a risk of falling and measures are mandatory; measures must also be taken at a lower fall height if there is a risk of falling. Collective measures, such as scaffolding or roof-edge protection, take precedence over individual measures such as a harness.
That is why during a renovation there is usually scaffolding along the gutter. A gutter is not a support point: anyone who leans a ladder against it or leans on it can damage the gutter and slip. So as a private individual, do not climb onto the roof yourself just to straighten a tile. If the scaffolding stands partly on the neighbours' land, make arrangements in advance; see Renovating and the neighbours.
VvE, rented homes and who does the work
If you live in a flat, the roof is generally one of the shared parts and renovation is a matter for the vereniging van eigenaren (VvE, owners' association); exactly what is shared is set out in the splitsingsakte (deed of division). The roof then belongs in the long-term maintenance plan. See Renovating a flat with a VvE. If you rent, major maintenance of the roof is a matter for the landlord; report defects in writing. If you want to have insulation installed yourself, first ask for permission in writing; this is generally required for changes that cannot easily be undone at the end of the tenancy (Article 7:215 of the Dutch Civil Code).
Renovating a tiled roof is work for a roofer who specialises in pitched roofs. Carpentry, such as new roof boarding, repairing rafters or wood rot in the fascia boards, is done by the roofer themselves or they bring in a carpenter. Lead and zinc work is for the roofer or a specialist zinc worker.
About quality marks: Dakmerk is a quality mark for flat roofs and therefore says little about a tiled roof. For companies that cover pitched roofs, Gebouwschil Nederland is the trade association for roofing and façade specialists; we have not found a separate quality mark for tiled roofs with its own guarantee scheme. So ask for references of similar roofs, the business liability insurance and the guarantee. You can read more about quality marks in Quality marks in construction explained.
What belongs in the quote?
Preferably request two or three quotes based on a visit, during which the roofer also looks in the attic. Check that the quote states:
- the area of the roof and exactly what will be done: repair, partial or full renovation;
- whether the tiles will be reused or replaced, and if so which type, which colour and how broken tiles will be supplemented;
- the underlay, counter-battens and tiling battens, and how the roof boarding will be checked;
- the insulation: inside or outside, material, thickness and the Rc or Rd value, and the vapour control and vapour-permeable layers;
- the ridge and ridge tiles, the lead and zinc work and the connections to the gutter, chimney and roof windows;
- the ventilation under the tiles and the bird protection at the foot of the roof;
- the scaffolding and fall protection, and who arranges them;
- how additional work will be charged if the boarding or rafters turn out to be rotten, if asbestos is found or if there are nests;
- disposal of old material, the schedule, the guarantee and the insurance;
- an invoice with the split between insulation work and other work for VAT purposes and the details you need for the ISDE.
How to compare quotes fairly is explained in Comparing quotes: how to read a building quote.
In summary: have loose tiles and lead repaired promptly, and choose renovation if battens, underlay and tiles are affected across the whole roof. That is also the moment to insulate, to think about birds and asbestos and to prepare for solar panels. On VerbouwPro you post your job free of charge and roofers from your region respond.