Author Topic: Decorative Steps  (Read 1076 times)

Alan Sargent

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Decorative Steps
« on: August 07, 2016, 05:50:51 pm »
DECORATIVE STEPS – Guidance Notes for Garden Designers.

Perhaps the most important element of garden design is the construction or ‘hard landscaping’ aspect of the designers’ craft. Choose the wrong plant, and it may be changed with minimum disruption. If the colour scheme of soft landscaping requires altering, a different selection of plant varieties may be introduced.

However, the most expensive part of a ‘New Build’ scheme – the paving, walling and steps and the specification thereof - are often seen as the responsibility of the architect or left in the hands of the builder, as though they were beyond the design abilities of a garden designer. More often than not, even the works involved in constructing the driveway – and choice of materials – is not included in the designers brief, and this exclusion can be to the overall detriment of the scheme.

Once the ‘Builder’ has left site, the designer is left to pick up the pieces and try to design around someone else’s vision of hard landscaping, and instead of creating a complete and harmonious picture, may have to work hard to incorporate various fixed features into the design proposals.

Very often, this is a case of becoming involved too late in the day.  The garden design may be an  after-thought, secondary to making the property inhabitable, and as you are perfectly capable of offering choice and expertise to your client, the earlier you are locked into a scheme, the better. You will be in competition with the Architect (or Builder) who has a vested interest in being engaged to design the hard landscaping, and in order to prove your worthiness, you will need to introduce your knowledge at the earliest opportunity.

This is the greatest challenge to your marketing skills, but by having information, samples and technical data readily available at the outset, you will at least make an impact with your client. The larger the selection of appropriate and well - chosen samples of materials and their attributes for use you can supply on site the better. I cannot advise on that selection, as it will vary from region to region, and the use for which it will be recommended, but it should include physical materials (shown both wet and dry for colour variations) and relevant fixatives, mortar colour swatches and available dimensions.

I have nearly fifty years  of experience in constructing gardens throughout Europe (predominantly U.K. Mainland), working with a wide range of natural stone materials. Since the early 90s, I have been involved with specifying stone, especially for use as paving. I was part of the Traditional Paving Development Group based at UWE (University of the West of England, Bristol) Frenchay Campus, demonstrating and specifying various techniques of working with those ‘old fashioned’ materials such as granite, York stone, ironstone and Portland. My role was to demonstrate these techniques in a practical ‘hands on’ manner to other specifiers, especially those employed by Local Authorities (Conservation Officers) and Architectural practices.

This work lead me to become involved in practical training and trouble -shooting when schemes go wrong. Unfortunately, the number of failed projects seems to rise year on year, as more and more ‘new’ products are introduced into the marketplace. Many of these materials are excellent additions to the product range available to designers, but unfortunately, too many are unsuited to the conditions and use for which they are specified.

Design Using Product Specific Logic

It would be more accurate to say that the methodology in construction is often not product specific. Certain materials may be described as ‘Designer’, and are offered to clients simply because they are the latest on the market, or have become fashionable due to exposure at Chelsea or other Shows.

It is too simplistic to say that these products are not suited to a particular site. However, it may be the form in which they are supplied that causes schemes to fail. Take natural sandstone for an example. Until the mid 80s, ‘sandstone’ usually meant York Stone, which was available in several forms, including sawn six sides, riven, random rectangular, reclaimed, setts, cobbles and a host of other shapes, sizes and thicknesses. The material was often of variable quality; reclaimed may mean ex-street, where town paths had been replaced with more modern concrete setts or slabs at the behest of a Local Authority, keen to refurbish and modernise a shopping centre. Reclaimed could also mean ex-factory floor, where it may have been contaminated with various oils and chemicals, totally unsuited for use in sunlight, where the heat would bring out these unpleasant features, becoming evident only once installed.

The skill of the designer/landscaper was to know the difference between the various types and their province. ‘Deep dug’ paving is far denser and harder than surface stone, which is harvested only from shallow excavations and is therefore more expensive. Deep Dug stone requires a period of ‘resting’; left above ground and covered with soil to prevent frost damage whilst the stone becomes acclimatised to its’ new, less stressed situation. This de-stressing is essential to avoid cracking and delamination if sawn too soon.

Sandstone is still ‘York Stone’, but there are also many dozens of different sand stones that have been imported from India, sold as ‘York Green’ or ‘York Stone’.  These imports tend to be far denser with less porosity and greater crushing strength that U.K. sand stone. They are also sold in uniform thicknesses, achieved by passing the slabs under a special machine, usually as thin tiles averaging 22mm, in a range of sizes (up to 900mm x 1200mm)

Many more types are now readily available. Ceramics are the latest addition to the range, and the ease with which these products may be packaged, crated and supplied makes life so much easier and more predictable for the contractor. Uniform thickness, uniform gauged sizes in a range of neatly fitting patterns with regular joints all lend themselves to make life simpler and more profitable.

There is however, a very important factor that is often overlooked by designers and contractors. Put simply, these ‘designer’ products, and the manner in which they are sold, require a profound knowledge of how the whole construction process should be approached. These uniform sized, easy to handle and use products are simply cosmetics. They are outer window dressings being installed for use as steps, paths and wall cladding, and must be treated as veneers.

Ensure the Whole Structure is Sound Before Cladding

I have chosen the construction  of steps as the title for this article, as they cover the whole gamut of problems associated with veneer cladding, involving ‘walls’ in the shape of sides and risers. Very often stand - alone features creating safe access from one level to another, but also fixed features, attached to the front, side or rear of a building.

Stand - alone steps require adequate foundations to prevent the whole from breaking apart, or slabs/side rails from becoming loose through movement in the main base construction. It may be necessary to design ‘heel and toe’ foundations to prevent slippage. Fixed steps may also be prone to collapse, but the evidence of movement will be more easily noticed if they break away from the main house walls.

To give some examples of recent projects I have been called on to produce reports in my capacity as a Gardens Consultant (specialising in construction and Historic Gardens) where schemes have failed, often within three or four years from practical completion and therefore out of normal warranty terms. (Nevertheless, they may prove negative to a designers’ reputation).

The first project was completed in accordance with the designers drawings, which showed only the effect desired, with no construction plans or details. The method of building the work was left entirely up to the contractor. The scheme was won on price, and it may be presumed that the technique was developed by the contractor as their preferred specification, and perhaps they may have avoided similar problems in the past due to working on a different site.

Their foundations, including risers and base raft for a Stand Alone flight of six steps, each 1.8m wide, with side rails, were constructed in pressure treated softwood timber ‘sleepers’, covered in expanded metal sheeting affixed to the timbers. Each sleeper was secured using metal locking screws.  The risers were finished in mortar render, as were the side rails. The coping and treads were clad in 22mm Indian Sandstone, laid on a 25mm bed joint of mortar. The slabs were pointed in a similar mortar mix.

The site in this case was on light sandy soil, with a high level of acidity and subject to water run-off from higher ground. The acid and moisture reacted with the timber and its’ metal fixings, and the whole ‘foundation’ started to flex within itself especially during hot weather. The result was that the paving veneer became loose, the steps became dangerous to walk on, and the side rail copings slipped.

A second project was constructed using lightweight thermal walling blocks, which were rendered in a similar manner, with Portland stone steps and side rails. Again, the steps were Stand Alone, and also on wet sandy soil. This time however, the problem that occurred was that of expansion and frost damage. The thermal blocks were chosen by the contractor because they were easy to cut accurately using a standard hand saw, and therefore provided a quick and neat construction technique when building the steps. Photographs of the completed project showed an award winning scheme, with superb finish and neat workmanship. However, within three years, the scheme needed a total rebuild, this time using solid concrete blocks.

The final example is a project involving stone steps leading from the rear door of a property, eight in number, approximately 1.5m wide, with metal railings acting as a handrail. Here, the contractor had produced a sound scheme, using solid concrete blocks and a substantial concrete foundation. However, the steps were built after laying the lower footings, straight on to the concrete foundation without tying the two elements together with reinforcing bars set into the base foundation and protruding above ground and integrated into the lower concrete blocks. The weight of the steps pressing downwards was sufficient to move the whole structure forward and away from the house, with the base foundation acting as a slip plane.

Each one of these schemes would have been presented to the client as superb examples of the work of the designer and contractor. The completed projects would have been well received, yet they all subsequently  failed because the builder had not recognised the essential requirements for the structure to be 100% solid and well thought out. Too much emphasis was placed on the cosmetic finish, combined with the lowest price, easiest handling methods and fastest completion of a pretty scheme. A short working period equals a happy customer and more profits for everybody.

I am sure that there was no intention on the part of anyone involved to ‘cheat’ the customer. There is absolutely no point in gaining a reputation for failure of schemes within  a few short years.

I would submit though, that if designers and contractors worked together to produce schemes that show clear understanding of the importance of the main construction, the technical aspects and engineering elements of the build, then cost would not be an issue. Getting the client to appreciate the absolute requirements for sound construction is not difficult. Price becomes secondary.

I well remember one of my clients who accepted a comparatively  high price to build a flight of twenty Stand Alone steps on a steep bank in Surrey. He came out from the house during the ‘concrete pour’ element of the job, took one look at the amount at steel reinforcing sheets and bars, the timber shuttering and depth of concrete. He stroked his chin and said “Now I know where the money is going” turned around and went back into his home office, a very satisfied customer (who went on to spend many thousands more on other projects in the same garden, without questioning anything!)

Alan Sargent FCIHort
Alan Sargent Consultancy Ltd
August 2016

(Alan is an Independent Gardens Consultant, Founder of The Association of Professional Landscapers and The Association of Senior Garden Advisers.)  See also