What are the Elements of Quality in Timber Windows and Doors?

January 8, 2019

Timber windows and doors – built to last

We choose to promote products which are well designed, beautifully constructed and finished. Most importantly though, they are built to last a lifetime.

But every salesman says that, right? So what are the things you need to know to make an informed choice of product?

When I got my first job I bought a herringbone jacket from Austin Reed for about £150. A lot of money then, but I didn’t have to replace that jacket for 25 years. And that was only because the pockets had started to sag a little. Its replacement was in a Jaeger sale for £180.

new suit
A new suit: which is £50; which is £450?

Just like a high quality garment, a durable timber product will depend on various factors:

Design – Standard or Specialist?

Are the products manufactured to standard patterns, or in-house designs?

The majority of UK and overseas fenestration manufacturers make their products to relatively unsophisticated ‘off-the-shelf’ patterns. Smaller independents use these patterns because they don’t specialise in windows and doors. They probably make staircases and kitchens as well.

Timber window
Standard profile: wide gap around casement, visible hardware, poor weatherproofing, less robust frame
Specialist profile: snug casement, concealed hardware, excellent weatherproofing, more substantial frame less prone to warping

A specialist manufacturer is more likely to use designs developed and perfected in-house. They use knowledge gained from many years of experience and previous installations.

What is the main material?

Softwood or Hardwood: What type and class or grade is it? Is it solid or finger-jointed and/or engineered? Is it treated? How is it treated? Does it have any parts that are not timber, i.e. MDF drip bars, cills, or resin beadings/glazing bars? Are glazing bars stuck on individually or jointed?

We have seen softwood products that have rotted within only six years of installation. They were imported products, “guaranteed” by a company whose quotations we sometimes ‘compete’ with. Usually about 30% cheaper than the products we recommend, their specification is considerably inferior.

rotten window and door
Cheap imported timber product: less than 6 years old. Part of a full house of windows and doors, all completely rotten

Earlier this year, a Client of mine chose my recommended products over the same importer. This was partly because he’d been told their quotation was for ‘hardwood’. The Client showed me the specification which clearly stated ‘European Redwood’ as the main material. I suggested he ‘Google’ it, and he found it was actually softwood. Also, his order comprised several doors – we would NEVER recommend softwood doors.

Did you know balsa wood is classed as a hardwood? So just because it’s hardwood doesn’t necessarily mean your product will perform better than if made out of a quality softwood. It depends on the timber.

We recommend products made from engineered Sapele Mahogany which weighs approximately 590kg per cubic metre. Many other hardwood products are made out of the cheaper solid or engineered Red Grandis. This is lighter, at 500kg per cubic metre, BUT the variation in quality means the weight can vary +/- 20%. The product durability can therefore suffer accordingly.

Timber sliding sash windows Harrogate Yorkshire
Best UK manufactured: 12 years old – no repair or decoration required

What is the glazing specification?

All products must comply with building regulations for thermal performance and safety as standard. Do your quoted products comply? If your project is new-build, do they comply with new-build part Q requirements?

Most products will meet the minimum requirements. Those that we recommend exceed them. For example, the minimum thermal performance of a whole window unit, as required by Building Regulations, is 2.0. This takes a combination of the U-values of all parts of the window – frame, glazing units etc. – into account. Many products will comply with, but not necessarily exceed this value. A lower, and therefore more efficient, 1.4 whole unit value is considered ‘good’. This value is easily achieved by the timber products we recommend, and some of them perform even better than this.

How is the glazing installed?

Is the glazing fitted with silicone or glazing tape?

cheap metal window spacer
Cheap metal spacer = less efficient. Glazing fixed with unsightly silicone sealant

warm edge window spacer
Warm edge spacer = best thermal performance. High quality glazing tape.

Many cheaper products use silicone – especially those that have been imported. Silicone not only looks unsightly, it also gets dirty quickly and starts to degrade within a few years. Cheap glazing tape isn’t much better, and if your product has glazing bars, these will start to come off in time.

Are the beading sections and glazing bars separate?

stick on window bars
‘Stick-on’ bars warping & lifting. Silicone to beading degrading (5 years old).
stick on window bar joints
‘Stick-on’ bar joints collecting dirt. Silicone fixing degrading (18 months old).

Separate pieces allow water penetration to the joints and stick-on glazing bars will often warp and lift off within a few years.

Fully jointed window beading bars
Fully jointed beading and bars fixed with high quality glazing tape – 14 years old: no warping, twisting, lifting or redecoration required

Fixtures & Fittings

Is the hardware branded and fit for purpose?

There is a wide variety of hardware available, and the quality from range to range varies considerably. For example, friction hinges for casement windows can be made from cheap alloy or stainless steel. The former is relatively easy to bend and break. Cheap and flimsy spring balances for sliding sash windows can cost a few pounds per set. Those in our sash windows cost more, but they have been tested to the equivalent of 100 years’ use. They can also handle up to 50kg per sash.

Basic ex-VAT hardware price ranges:

  • Friction hinges (side hung casements): less than £5 to more than £15
  • Spring balances (per pair, sliding sash windows): less than £10 to more than £25
  • Espagnolette locking handles (casement windows): less than £5 to more than £15*

*premium handle designs can reach unit costs in excess of £60

How and where is it manufactured?

Is the product hand-finished or is the manufacturing mainly automated?

Some element of preparation by hand prior to painting will usually indicate a better product. Most overseas, and a number of UK competitors, do not include this element at all, which means their jointing and paint finishing suffers, compromising the aesthetics and durability.

Because different timbers behave in difference ways, our recommended products are all prepared by hand before painting to ensure the grain is optimised for coating. Then they are hand-sprayed, and lightly rubbed down between each coat. Each coat dries for a minimum of 12 hours to ensure optimum curing.

Specialist window and door manufacturing
Specialist manufacturing: a marriage of automated machining for accuracy & hand finishing for aesthetics & durability

Can you visit the workshop?

We only recommend products manufactured in the UK. Whilst it is no guarantee of better quality, at least you have some chance of redress if the product fails. In the example above, the unfortunate purchaser was passed from pillar to post, with the supplier blaming the overseas manufacturer.

Can I Get A Discount?

We all like discounts. If you negotiate 20% off a product that can only mean good value, right?

Have you ever asked for a discount on new premium product such as a car or watch? You might have been given a small token discount, if you were lucky. If it’s a product tailored to your personal requirements, you would be lucky to get any discount at all. So why expect a discount for your high quality bespoke windows and doors?

We blame the big nationals – and the 80s.

First, add massive mark-ups to products which have cost relatively little to manufacture (see Product 1 below).

Second, spend as much on marketing, if not more, than the product costs to make.

Third, offer everyone massive discounts (which vary depending on how long it takes to the get the Client to say ‘yes’). They’re happy – they think they’re getting a bargain. Product 1 below has alot of ‘wriggle room’ on the price, and will still make a profit if you get a 50% ‘discount’!

Unfortunately most of the industry works this way even today. Product 2 is a more realistic view of what is within the cost of a high quality product.

In the next blog we will give some advice on how to make your choice of product.

Robert Goldsbrough

Robert Goldsbrough

Robert has been developing and building period & contemporary homes since 1995, and has installed all types of external home improvement products.