Improve your property with skylights

Sunsquare is a designer and manufacturer of bespoke skylights to be awarded a BSI Kitemark in the industry. As an expert in his field, MD of the company Justin Seldis talks through the legislation concerning installation for landlords

Property maintenance will inevitably sometimes mean replacing or upgrading elements of your housing stock, rather than simply working on improving existing features. If you’re carrying out maintenance work on the roof, adding a rooflight can create a stand-out feature that will impress both current and future tenants. Planning permission can be a sticking point when it comes to making alterations to any property. But with skylights, wrangling over approval is less common than you might think.

This is usually because a skylight falls in as part of an already agreed extension, or it’s a replacement of an existing window. However, just because it is rare to come up against objections, doesn’t mean it doesn’t happen. It is always important to seek advice before you go ahead with making any changes.

In England and Wales, the insertion of new roof windows is subject to the current limits and conditions stipulated by the government’s Planning Portal. This comes under Schedule 2, article 3, part 1, class C permitted development.

It states that:

  1. Any alteration cannot project more than 150 millimetres from the existing roof plane.
  2. No alteration can be greater than the highest part of the existing roof.
  3. Side-facing windows must be obscure glazed with any opening to be made 1.7 metres above the floor

If your project fails to comply with one or more of the above, then your development won’t be permitted and a second application would need to be resubmitted following amendments to your plans.

Generally pyramid or lantern skylights are more of a problem as they stick above the parapet and can create an eyesore to neighbours.

If the property in which you want to install a new skylight is a listed building, or in a designated conservation area, then you should check with your local planning authority before carrying out any work.

Additionally, there may be specific types of planning restriction that mean certain works which could normally be undertaken will be the subject of control.

It’s important to note that planning laws in Scotland are rather different than those in England and Wales.

Planning permission for roof windows is often required for even the most straightforward of skylight designs and Scottish property owners should contact their local authority to work out the best way forward.

Similarly, homeowners in Ireland should also contact their local authority for advice because failure to obtain permission where it is required can result in penalties – including imprisonment.

Building regulations are an issue quite separate to planning permission and should always be taken seriously. After all, the removal, addition or alteration of a skylight can have a detrimental impact on a roof which can, in turn, make a building unsafe.

Even if planning permission is not required, building regulations cannot be ignored.

By law, any building or structural modification work must comply with building controls which stipulate minimum standards for design and safety.

There are two sets of building regulations for roofs – work on an existing roof and the construction of a new roof.

Be sure to pay particular attention to Parts J and L of Building Regulations; these deal with energy efficiency, thermal insulation and the protection of buildings against the threat of fire.

Approval under the Building Regulations will generally be needed for the installation of a new rooflight for the following reasons:

  • To install a new rooflight, the roof structure will often need to be altered to create the opening.
  • The roof will have to be able to carry the weight of the new skylight. If the roof is not able to do so it will need to be strengthened prior to installation.
  • Any rooflight installed must prove it has sufficient insulation against heat loss with effective energy performance.
  • In the event a skylight is in close proximity to a boundary, its fire performance must also be taken into consideration.

To install a rooflight in a roof you will often need to cut part of one or more of the roof’s rafters or joists away. You will need to fit a new support for the cut ends of the rafter or joist in question. Adjacent rafters or joists may also need strengthening, as they will be supporting the load transferred from the cut rafters or joists.

Any room that a skylight is designed to serve will also need to be well ventilated. This can be achieved using the skylight itself for both rapid and background venting.

In terms of energy performance, any window or door must comply with the minimum requirements of the Building Regulations in relation to the amount of heat that can pass through a window or door, including the frame.

This is known and measured as a U-Value. This U-Value should not be exceeded.