We’ve produced the below based on the questions most frequently asked of us. We hope that you find it useful.

Renka are a family run company based in the Midlands, but covering the whole of the UK. The company has been going since 2006 and still keeps true to the family values that lay behind its formation. The management team has a wealth of both general construction experience and aluminium industry knowledge, and prides itself on taking real ownership of every project we get involved in.

Renka’s projects cover a wide range of residential work, from single products to full new builds, and some commercial work.

  • Over 100 years’ combined experience of all aspects of aluminium , UPVC and general construction.
  • Our surveyors will work closely with you, your architect and builder to help bring your ideas to fruition.
  • An experienced, thorough and professional sales team who are there to present and discuss your options, and advise on how best to achieve your vision.
  • A large Birmingham-based showroom with a wide range of products on show.
  • A 22,000 square foot manufacturing facility with state-of-the art production equipment.
  • An Installations Team who are specialists in working with the unique requirements of aluminium glazing.
  • A personal and professional approach to all we do, combined with the determination to deliver an exceptional level of customer service.

Renka can supply and install a wide range of aluminium framed products, including :

  • Sliding and bifold doors
  • Casement, tilt and turn, sash, bay and bow windows
  • Oriel and frameless windows
  • Fixed glazed panels, fixed shaped panels and gable glazing
  • Glazed single and double / French doors
  • Residential entrance doors
  • Curtain walling
  • Flat, double hipped and monopitch rooflights. Bespoke structural and bespoke glazed roofs.
  • Balustrades

We can also supply and fit some a range of high quality UPVC door and window ranges

When we first make contact, we will want to understand what you’re trying to achieve. This will enable us to start considering what products will (or will not) deliver your vision.

To enable us to provide you with a quote, we will need to know a number of things:

  • Where geographically the project is?
  • What products you are considering?
  • The expected size of each product?
  • The configuration of each product:
    • In the case of sliding doors, how many panels you want and which of these you want to slide.
    • In the case of bifold doors, how many panels you want and how you want these to fold, and
    • In the case of windows, how many panes you want and which of these should be fixed or openable.
  • Your preferred colour for the products.

Please don’t worry if you aren’t certain of all of the above information, as it’s our job to help you to consider all your options and help you decide what products will best deliver your vision for how you want your house to be.

If you have had plans and elevations drawn up, we will ask you for PDF copies of these so that we can have the clearest possible understanding of what you’re looking to achieve and where each product will be going.

The quote that you receive from us will be clear and concise, will use easy to understand language, and will avoid the use of overly technical terminology. We will include the costings for any different product or configuration options, and will include detail on the system(s) that we’re recommending, and the benefits of each of these.

In virtually all of our quotes we will include a clear separate confirmation of the cost of installing the products, or, if requested to do so, of JUST supplying and delivering the products for installation by others.

As a matter of course, within the e-mail that the quote comes out on, we will also look to identify for you any design or other considerations that may affect the practicality or cost of the design.

The vast majority of the doors, windows and roof glazing we supply and install are made to suit client and site specific requirements. In most cases, we don’t offer any standard size products as it is much simpler for us to produce them to fit correctly into the created apertures than it is for architects and builders to work around a set size. We also try to keep our lead times as short as possible so that your project won’t be held up as we produce your bespoke products.

Renka supply and install products throughout the UK, so it’s very likely that we’d be able to install your doors and windows. We do not sub contract out any of our installation work so that we can control the quality of all our installations. We strongly believe that this a very important element of what we do, but it may well mean that our installation cost (which may involve travel to sometimes geographically distant areas and overnight accommodation) may be more costly than that quoted by a more local company.

The installation cost we quote you will assume a number of things:

  • That we are installing the products into prepared openings. If you want us to quote to remove existing products, please make us aware of this at the earliest point.
  • That there is good access to bring the aluminium frames and glazed units to the point of installation.
  • That safe access platforms / scaffolding will be provided where the point of installation for certain products may require this. Unless explicitly stated in the quote, no allowance has been made for the provision of mechanical or powered lifting equipment.

Our quoted installation cost includes transport of goods to site (including by specialist transport if required), technical site survey, provision of any technical drawings required, and liaison with architects, builders and any other relevant contractors. Installation is by fully qualified and trained Renka fitters.

Renka manufacture the majority of products we supply and install. In addition to this, we have access to a wide range of other high quality products available across the market in order to offer you the best combination of look and functionality for your project. The products we supply and install include (but are not limited to) those by Cortizo, Reynaers, Smarts, Hormann and Deceuninck.

All Renka products benefit from :

  • A 10 year guarantee for structural integrity and mechanical operation.
  • A 10 year guarantee for the installations carried out by Renka’s in-house installation team.
  • A 5 year guarantee for Renka supplied double and triple glazed glass units

Renka’s guarantees are based on the supplied products being used in the correct way and maintained properly to maximise their look and performance.

A number of factors affect the uValues of Renka’s supplied products, including :

  • The product specified
  • The product design / configuration, including the number of panels / panes.
  • The glass specified

In general the most thermally efficient part of a particular product is the glass (typical centre pane uValue of 1.0 on a double glazed unit and 0.8 on a triple glazed unit). The more frame / mullions and transoms a product has, this will reduce the products’ thermal performance.

If you are looking to achieve a particular uValue, please advise us.

RAL refers to a European colour matching system used for powder coating paint, amongst other applications. Depending on the product(s) being discussed, door and window frames can be powder coated in over in 150 different RAL colours to ensure there’s a look to suit you and your home.

Colour can affect the cost of some, but not all products. Most products have a small number of “standard” RAL colours – normally white, black and anthracite grey. In these cases, other colours will come at an additional cost.

To help you decide which colours you particularly like, you can use the attached link to an online RAL colour chart:


Powder coating refers to applying a free-flowing powdered paint to an object using finely ground dry paint particles which are electro-statically charged. Once the powder has been applied, the object is then heated in an oven at a very high temperature so the powder particles bond together to create a smooth, uniform and highly durable finish.

Powder coating is much more environmentally friendly than liquid paint as it contains no volatile organic compounds (VOC), heavy metals or solvents, meaning that the paint poses no threat to human health or the environment.

The process also produces minimal waste. Traditional spray painting with liquid paint results in a lot of wastage through over spraying, meaning that any excess paint used in the application can’t be recycled. Any over spraying during the powder coating can be collected and recycled instead of filtering into the environment in the form of air and water pollution.

“Marine-grade” is a term that refers to the depth of a paint finish to be applied to products to be used in a coastal or marine environment where the corrosive effect of salt water can affect metal-based products. Paint thickness is measured in microns, and marine grade paint is generally understood to have a paint thickness / depth of 60 to 80 microns. Whilst most of our products have paint of marine grade depth as standard. However, If your project may require marine grade paint, please make sure that Renka are aware of this.

Having “marine grade” paint on products does NOT prevent them from being affected by salt water in the environment, and a regular regime of cleaning to remove the salt deposits is strongly recommended to maximise the life and appearance of the products.

Yes. Our frames can be powder coated different colours on the inside and outside of the frame. With this dual colour option available, it means that the exterior colour can complement the building style while the interior frame can blend in with or contrast your internal colour scheme. This does add to the cost of the product(s), and the amount by which it increases the cost depends on the product(s) specified, so please discuss this with us.

The majority of our products come specified with 28mm double glazed argon filled units. Triple glazed units can also be specified for the majority of products which will offer better thermal efficiency (uValues), but come at an additional cost.

For South facing products / those with significant exposure to solar heat, we can specify solar control glass which will significantly reduce the heat transmission from the outside to the inside of a property.

For properties that may be immediately adjacent to a road, acoustic glass units can be specified which improve the noise reduction achieved by normal glass.

For certain applications and products, laminated glass (which stays in situ if broken) should / will be specified.

Tinted and reflective glass are not available on doors, windows and fixed glazed panels from Renka. Post installation / after market films are available for application to windows and doors.

Renka can offer double glazed units with integral magnetically operated blinds for installation in certain windows, single doors and bifold door leafs. These operate using 2 very strong magnets – one of which by moving circa 3 – 4 inch will change the blinds from their open to closed position. The second, by moving it 9 to 12 inches will allow the blinds to be raised to stack at the top of the glass unit.

We unfortunately can’t offer integral blinds for installation in most sliding doors, or wide windows, as the maximum width for integral blinds is 1.2 metres.

Yes – Renka can specify windows in many different shapes and sizes – round or shaped windows are not a problem. Depending on the product concerned, it may be necessary for a template to be produced to allow the accurate production of the frame and glazed units.

Most products are easy to use and maintain – needing only regular cleaning to maintain their appearance – the powder-coated aluminium external frame will resist even the harshest weather conditions. The best method of cleaning is by regular washing with a solution of lukewarm water and mild detergent . All surfaces should be cleaned using a soft cloth or sponge, and nothing harsher than natural bristle brushes.

To maintain the operation of moving / mechanical components, all moving parts should be cleaned and lubricated with acid-free oil once a year.

All our systems allow for a flush finish to internal floors, meaning no step up to get out to your garden / patio.

  • Our sliding systems can allow a completely flush finish between internal and external floors (providing adequate drainage is in place).
  • To ensure bi folding doors are weather tight, a small rebated upstand from the internal to the external is recommended to guarantee years of trouble free use.

In either case, the sooner we can be involved in detailed discussions with you / your builder, the better we’re able to ensure that the end solution is what you’re looking for.

All of our sliding and bifold doors are bottom running, meaning there is no weight in the head of the doors.

The steel above our products are to give a level / non deflecting line that the frame is fixed into.

Whilst we install the vast majority of the products we supply, we CAN offer virtually all of our products on supply only terms for installation by others. Where products are provided on supply only terms, we will aim to provide any technical information required by your installers. We will advise you if we feel that due to the technical nature of some of our products, we should be supplying AND installing them.

In the vast majority of cases, Renka will carry out a site survey in order to :

  • Establish manufacturing sizes of every product
  • Agree details such as Final Finished Floor Level, cill requirements / detail, and construction order and timing.
  • Work through any remaining details about the project that need to be finalised.
  • Agree any actions that need to be taken on site prior to the installation of products.

In order for us to carry out a site survey, ideally your openings will need the steel/RSJ in place and other apertures fully formed.

In some cases is possible to carry out a survey without the opening being fully ready. However, the manufacturing sizes will need to be agreed and signed off by the client or their representatives before manufacture takes place.

In some cases, Renka will, at the client’s request, produce products to pre agreed sizes without a site survey, on the understanding that the installation of these into apertures is at the client’s responsibility.

A Lead time can normally only start when we have final sizes and configurations of all products.

Our lead times fluctuate slightly through the year depending upon demand. Non standard RAL coloured products may also extend the normal lead times. The lead time for manufacture of products may also at times differ from the lead time for booking the resource of our Installations Team.

Whilst we will wherever possible work towards supporting your project schedule, this may not always be possible.

Our sales staff will always aim during the quote process and at the point of order to be clear on what our lead time is likely to be on your project.

Our bifold systems can support panel sizes of up to 3 metres in height and with panel widths of up to 1200mm.

We tend to recommend the minimum amount of panels possible within a run of bi folding doors as this improves the overall aesthetic of the door due to maximising the glazed area. This is also a more cost effective option as the additional components in each panel does have a heavy impact on the overall price.

An odd number of panels in a set of bifold doors also offers the opportunity to have an independent traffic door.

We have a range of sliding door systems available. These offer a range of maximum sizes for each panel, up to 4 metres wide or 4 metres tall.

How many panels you prefer to have will largely be determined by how much of the total aperture width you want to be openable at any point in time. On 2 and 4 panel configurations, roughly 1/2 of the span can be opened. On 3 panel configurations, roughly 2/3 of the span can be opened.

In this case, if you let us know, we will then raise a formal Order Confirmation for the project. The Order Confirmation formalises details of :

  • The products involved
  • Their EXPECTED (pre survey) dimensions
  • Their expected colour and configuration
  • Their costs
  • The overall project costs
  • Our payment terms

We will issue this and ask for :

  • It to be signed and returned
  • Confirmation of when you expect to be ready for a site survey (normally when all apertures are fully formed).
  • 50% deposit payment.

As soon as we have the signed Order Confirmation and deposit payment, we are able to order in the “profile” (raw materials). This has the benefit of reducing by 2 to 3 weeks the lead time for manufacture of products from when we establish “made sizes” (manufacturing sizes) at point of survey.

When we have carried out the site survey, we will issue a POST SURVEY ORDER CONFIRMATION to you confirming made sizes and any other relevant details, and will request that this be signed and returned to allow us to schedule all products in for final manufacture.

If you use Renka for the direct replacement of existing windows and doors without changing their apertures, you may not have to apply for approval from Local Authority Building Control. Renka is continually assessed by FENSA to ensure compliance with the Building Regulation requirements, and the FENSA scheme rules.

In this case, FENSA will provide you with a certificate which confirms that the installation work has been self certified as complying with the Building Regulations. This is something you may need if you sell your property. Although registration with FENSA is voluntary, we believe that our registration with FENSA is an important part of what we do, as it gives our customers extra peace of mind.