Portland Stone News

Thresholds and The Landscape Designer

Article courtesy of The Landscape Libary

In recent years, it has become more and more common for home owners to demand that their patio paving is laid at the same level as the doors and other thresholds as their interior flooring, thus creating a seamless hard landscaping ‘carpet’, often requiring the same product, laid on the external patio as used on the internal flooring – usually tiling thickness porcelain or ceramic units, matching the same colour and pattern to give an impression of infinity paving.

Owners demand that designers work on the brief of this seamlessness, without having any insight or knowledge of the technical factors and techniques used in the construction of their houses. They have seen it in magazines, their friends have something similar, and they want the same – even if their house if fifty years older than their friends new-build unit.

Designers, often reluctant to disoblige, go ahead and produce drawings and plans showing the same tiling throughout, even colour matching and instructing the contractor to use the same tiles including the manufacturer’s product code numbers and source of the original products.

Thus, the homeowner becomes encouraged to think that they can have this seamless effect without any problems.  The designer or owner duly involves a contractor, either as a Builder or Landscaper, and charges them with constructing the scheme, somehow making it work – even if the designer has not produced any cross sectional or technical drawings showing how this is to be achieved…

Read more on Thresholds in the full article here

Thresholds

Building Regulations

In England and Wales, the Building Regulations Document M Clause 6.19 is effective in the matter of thresholds and water ingress. This information is easily obtained from the Internet, but understanding how the subject effects the landscape industry is less clear. Anecdotal evidence is passed from one designer to another, landscapers discussing the topic unable to agree, because essentially, the type of property is less important as to how it was designed and constructed having due regard to water ingress and disability.

Put simply, the design of the internal floor and construction techniques employed in the house build and door type are critical. Unless the main building has been designed to permit such unimpeded access, with a series of special barriers and configurations to prevent not only water ingress, but also thermal insulation (to prevent capillary action or water ingress through hot air within the building, drawing moisture into the floor construction), no amount of external designing can mitigate potential problems with moisture.

The external approach to an entrance should consist of a reasonably level platform or ramp to provide an accessible threshold. This should slope away from the building by between 7 and 15 degrees to prevent rainwater from building up or being driven towards the building.

The threshold design must satisfy the provisions of The Building Regulations in respect of minimising the risk of water ingress or damp entering the building (Part C). This regulation goes on to mention vitally important elements of the house construction, that if a designer wishes to create a seamless vista, they should first of all contact the Architect of the building to obtain written instructions or receive a copy of the internal floor plans and cross-sectional drawings as used by the main Builder during construction works…

Read more on regulations by reading the full article here