Building regulations for conservatories

 

In the previous blog, I covered planning applications - the permission to build.

Here I am going to look at why some projects require further details to be submitted before you can start building your conservatory.

Most conservatories do not need Building regulations approval, but quite a few do and you will need to know what could apply to your project, to avoid making some potentially costly mistakes.

What are Building regulations?

Building regulations set the minimum? standards for the design and construction of buildings. These standards are applied and enforced through the building control system by private Building Control Companies or council appointed building officers, and are supported by technical guidance documents - also known as approved documents.

Independent or Council appointed Building Inspectors will inspect the project at various stages throughout the build, making sure that all the regulations are adhered to. Once the conservatory is completed, they will issue a certificate of approval –confirming that your conservatory has been built in accordance with building control standards.

If a conservatory does not require building regulation approval, there is no current legislation governing the quality of the building of that conservatory. This is an area for concern as the quality of the build is then entirely down to the agreement you have with the company you are dealing with – no one except you will be checking the quality of the work.

It is known for individuals and/or companies to ignore building regulations and not advise their clients to seek building regulation approval, or for individuals to ignore the need to do it, even though required by law to do so. This has several very real dangers:

·         The quality of the build is unlikely to be up to standards

·         If your project has not had building control approval when it should have, it is likely that your home insurance will be invalid in the event of a fire

·         When you try to sell your home, the survey on your house will show that no building control approval was given, frequently resulting in the loss of a sale or reduced offer

·         It is illegal

Do I need Building Regulation Approval?

There are several reasons your project may require building regulation approval. You will require building regulation approval if you answer YES to any of the following:

·         Your project is over 30 square metres internally

·         Less than 50% of the walls are glass

·         Less than 75% of the roof is glass

·         I am removing the doors dividing my house from the conservatory and leaving it open

·         I am extending the heating system from my house into the conservatory

·         I am removing the wall dividing my house from the conservatory and leaving it open

·         The door(s) dividing my house from the conservatory are not exterior quality doors

·         My conservatory will not be at ground level

What do building regulations take into account?

When a project is subject to building control, all aspects of the build will be considered. There are 2 ways to apply for building regulations.

1. Full Plans approval
2. Building notice

A full plans approval requires detailed drawings showing every specification of the proposed build. These drawings -and any additional details that may be requested -are checked against the technical guidance documents, and approved before work starts. An inspector then makes several inspections during the build to make sure the details are being followed, before making a final inspection and issuing a completion certificate.

A building notice removes many of the details for a project, and approval is gained by liaising with the building inspector on site as you go. This can be ok for very simple projects, but on more complex builds it can also lead to some major amendments on site which will often increase the cost (funny how it rarely decreases the cost!)

It is always best to submit for full plans approval which leaves the least possibility for changes to be required on site during the build.

The main areas the inspectors will be looking into are:

·         Soil Conditions

·         Structural Design

·         Thermal Heat Loss

·         Safety Glazing

·         Fire Safety

·         Ventilation

·         Electrical Works

Soil Conditions

The quality of the soil will affect the specification of the footings. This will also affect the cost of the footings and is a common reason companies ask for more money when the project starts.

If there is any concern with the soil, this should be investigated at the design stage and certainly before any quotation is confirmed. I often dig an inspection hole and have a look on the first site survey if I think there may be an issue.

The main things to look out for are:

Clay soil

High clay content in soil can cause movement in buildings, this is due to the expansion and contraction of the clay as it becomes wet and dry.

Tree Roots

Tree and hedge roots can grow a long way underground. Tree roots in particular have the ability to lift up buildings or disturb the soil around a building to the point where it can cause structural problems. Also, if a tree or hedge is to be removed as part of the project and the roots remain in or close to the build area, when the roots decompose they will lose volume and cause the soil to shift filling the voids and again potentially causing structural problems.

Drains

Most conservatories either run near to or over drains and/or inspection covers. Recently the water companies have taken over control of the mains that fall within private land where they feed more than 1 property - where a mains pipe branches off to feed just your property, this section remains your responsibility.

This will be more of an issue with semi-detached properties and terraced houses as any proposed conservatory within 3 metres of a ‘water company controlled’ mains pipe(whether subject to building regulations or not) will need approval from the local water company before the project can start.                         

This is called an application to build over or near to a mains drain and will include information showing  that the bottom of the footing closest to the drain must have a loading angle of 45 degrees falling below the drain invert, this can be calculated simply by measuring the depth of the drain and setting the correct footing depth.                                                                                                                  

Wells

More common than you may think - I have found 3 in my career so far - wells can be simple to deal with and they can also create some real challenges. My advice is to contact a structural engineer and/or the building inspector immediately. Wells can be filled and some can be supported and made into beautiful features inside the conservatory.

Unconsolidated ground

Ground that has been built up, filled in or covered over. A good example of this is on new developments. Some sites may have areas that have been filled, in order to level the site.

Water

If you live very close to a river or an area that floods, special attention will be required for the foundations.

Structural Design

Removing the walls that divide a conservatory and the existing building is a very popular way to extend a home. The loadings on the wall that is to be removed have to be calculated by a structural engineer and the method of support proposed. This is usually done with steel beams and sometimes oak beams.

For designs that have lantern roofs, calculations for supporting these may have to be made and designed into the final specification. Steel can again be used to support lanterns, however it is often preferred, where possible, to use Engineered timber beams also referred to as Glu-Lam beams (Glued and Laminated) This is because the engineered beams are less likely to attract moisture and cause problems with condensation.

Thermal Heat Loss

This applies when the wall dividing the conservatory is removed, leaving a permanent opening. The removal of the wall alters the thermal efficiency of the building, and where this is proposed, a heat loss calculation will need to be made.

Heat Loss calculations measure the CO2 emissions from the house as it currently stands, and a second calculation will measure the CO2 emissions from the house including the proposed conservatory. The second calculation including the conservatory, must show an improvement -in the form of a reduction- in the CO2 emissions of the building.

You will also require heat loss calculations if you;

• Extend your existing central heating system into your conservatory
• Install internal doors instead of exterior quality doors to new openings between the house and the conservatory.

Safety Glazing

Safety glazing applies to all glass in critical areas i.e. glass near doors,  low to the floor and in roofs. Glass requirements range from toughened glass (usually standard in all conservatories) to various levels of laminated glass.

Fire Safety

Typically affects conservatories when the proposed conservatory is directly under either  the sole window of a bedroom above, or structures that are on a boundary.

Ventilation

Correctly ventilating a conservatory for building regulations means that ample ventilation has been provided, particularly if the conservatory will form part of a new kitchen. This can be achieved with opening windows, doors, extractor fans and trickle ventilators. Additional roof ventilation should also be allowed for in the design, although this does not come under building control -I will discuss ventilating conservatories in the design chapter.

Electrical Works

Document P refers to the safe installation of electrical work, which has to be completed by a certified professional. This covers everything from sockets and switches to heating and lighting.

Building regulations are evolving all the time and requirements are altered regularly, therefore although this guide will hopefully help make a few things clear for you, you should always seek professional advice before proceeding with any project.

If you would like to chat with Matthew about any Building Regulation issues that you are concerned with, you can call him on 01603 869001.  http://www.morgan-bishop.co.uk/index.php