Design Problems and Their Solutions

Michael Holmes reveals the clever design solutions that will help you spot the hidden potential of any site.

"My Plot's in a Flood Area"

The Solution: If your plot is in a designated flood risk area (visit www.environment-agency.gov.uk to find out) there will be an assumption against development, or redevelopment (replacement dwelling), making it very difficult to get planning permission for a new home, or to renew an existing consent for a new dwelling. There are exceptions, however, and clever design is a key aspect of making your application an exceptional case.

You will need to find out the one-in-one hundred year flood level on the site, and design the floor levels above this. Parking, or other flood-compatible uses, should be designed at ground floor level, with the living accommodation at first floor level and above: a bungalow design is therefore unlikely to be acceptable, and basements are ruled out altogether.

The building’s construction will also have to be designed to withstand the expected water pressures, and potential debris impacts and erosion expected during a flood. In order to decide which resilience measures would be effective, you will need to find out the potential depth of flooding that is likely to occur from records. Flood resilience measures include: ‘dry proofing’ — measures to keep the flood water out using barriers across doorways and airbricks, and raising floor levels; and ‘wet proofing’ measures that accept that water will enter the building. This means raising sockets above the expected flood level and fitting tiled floors rather than carpets. Examples are given in the document Flood Resilient and Resistant Construction available at www.communities.gov.uk.

It will also be necessary to demonstrate that, where required, safe ‘dry’ access and escape is available from the building in flood conditions, and that there will be vehicular access to allow the emergency services to safely reach the property during a flood — this may involve building a raised causeway above the one-in-one hundred year flood level.

To increase your chances of success it would be worth engaging an architect with a successful track record of obtaining consent for one-off homes in a flood area.

LEFT: Jeremy Paxton’s spectacular riverside home in Berkshire is not just a feat of great design and engineering, but of brilliant negotiation with the local planning authority. The new design, which replaced a run-down boathouse that had been used as a dwelling, was obviously on the flood plain, but cleverly Jeremy argued that the new design would reduce the amount of actual building on the plain. The remainder, even on the lower floor, was positioned one metre about the 100 year flood level. The engineering story is no less impressive — sheet piling had to be inserted to secure and define the river bank, then foundation piles had to be driven in to support a concrete ring beam. All of this was done with the water constantly coming in

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"I've got a sloping site"

The Solution: A sloping site is more difficult to develop than a level site, but it often inspires a much more interesting design solution.

The steeper the slope, the more expensive it will be to develop: according to Brinkley’s Slope Law, proposed by author and H&R Contributing editor Mark Brinkley, each 1° of slope adds roughly 1% to overall construction costs.

Most design solutions involve creating a series of level terraces, by cutting and filling the ground, resulting in a floorplan on several different split-levels, often partially built into the slope, stepping either up or down the site depending on the direction of the gradient.

Good design should always take into account privacy, light and the potential to make the most of any views. On a sloping site it can often make sense to place bedrooms and bathrooms, utility rooms and storage on levels that have been dug into the slope, and to place living rooms at upper levels.

A very important consideration when designing a house to sit on a sloping site is access. The general principle is to let the vehicle do the climbing, so if the access to the property is above or below the road, a sloped vehicular access should be designed to lead all the way to a level area adjacent to a main entrance — usually the front door. This can involve considerable engineering works, landscaping and building retaining walls, all of which needs careful design and budgeting. It may be possible to get a relaxation of Part M of the building regulations for disabled access.

Due to cost, or the limited size of the plot, it is not always possible to create vehicular access directly to the main entrance of the property, and various design solutions have been used to overcome this, including lifts and ramps. An innovative alternative for sites that slope down and away is to create a bridged walkway leading from a level driveway directly to the front door at first floor level of the property.

"I'm restricting the right to light"

The Solution: Interrupting a neighbour’s daylight with your new home could infringe their right to light under civil law, even if you have planning permission to do so. This only tends to happen in urban areas where new houses are compact and due to restricted plot size, several storeys tall. Understanding the exact status of the neighbour’s rights, using a specialist surveyor to calculate the impact of your proposals on neighbours, will enable you to maximise the site’s potential, by designing the building to the optimum footprint, height and volume.

If you ignore this issue, an infringement of a right to light is likely to result in an affected neighbour seeking an injunction to reduce the size of your new home and could ultimately result in part of it having to be demolished. If you deal with the matter early you can negotiate, possibly at the same time as arranging party wall agreements, and you may be able to overcome the issue by paying some compensation for the loss of light. To find a specialist surveyor contact The Royal Institution of Chartered Surveyors www.rics.org.uk.

"I've got a tight urban site"

The Solution: Some small urban infill sites surrounded by neighbours can seem almost impossible to develop due to multiple planning restrictions, height limitations and the position of windows. A successful design solution for such a ‘backland’ site is to create a courtyard dwelling, with windows looking into a private internal courtyard around which the property is wrapped, creating maximum privacy and security.

Some outward facing windows can usually be incorporated, provided they are above eye level, or have obscured glazing, so as not to breach planning restrictions on overlooking neighbours. The opportunity to bring in light from above should also be explored.

A flat roof design will help keep the ridge height down. Often such designs have to be sunk down slightly by reducing ground levels, and if this is the case then it makes sense to build right up to the boundary where possible and to build the external walls of the dwelling itself as the retaining wall structure.

"I'm converting an Agricultural Building"

The Solution: Once a building such as a barn has consent for conversion there is often little you can do to alter the existing external appearance. This is because the justification for granting a change of use to residential is usually that this is the only way for the building to be restored and preserved and significant alteration would contradict this.

This policy can create a conflict when it comes to converting some buildings, especially barns, where consent for conversion includes a condition that no new window or door openings may be formed in the external walls. Some property owners overcome this by creating suitable window and door openings well before applying for consent for conversion, thus circumventing the system. This is not possible, however, once consent has been granted, as consents are almost exclusively full permissions, with accompanying drawings of both the existing building and approved conversion scheme. There are some options for introducing more light but these need to be negotiated with the planning authority and it is very much at their discretion. Successful solutions have included inserting conservation-style rooflights, and glazing sections of the roof between the existing rafters, both of which are more likely to be considered favourably if applied to the less prominent elevations. In the case of timber frame barns, some converters have managed to add glazing between some of the existing studwork on a less prominent gable, the argument being that the structure has remained unaltered.

RIGHT: Architect Nicholas Tye’s solution to introducing more light to his oak framed former grain store in Hertfordshire was to forego the more conventional rooflights and rely instead on a dramatic fully-glazed gable end, giving spectacular views.

"There's a size restriction on my replacement dwelling"

The Solution: The maximum size of the replacement dwelling will be guided by local planning policy, and most local authorities will have an adopted policy statement which you can view online, or at the council offices.

In all cases it is important to look at the reasoning behind the policy and to take this into account in your design. Policy is intended as a guideline and if your design is considered unsympathetic, then the policy is likely to be applied rigorously. If, however, your design takes on board other policy objectives and you negotiate with the case planning officer, taking a pre-application consultation, it may be possible to get support for a design that considerably exceeds policy. In particular, most policies restricting size are concerned with minimising the impact on the openness of the landscape, and so seek to minimise height, and what is known in planning terms as ‘massing’— which effectively means bulk. Keeping the ridgeline of the roof as low as possible is likely to be seen positively, as will breaking up the ridgeline and the main elevations.

Depending on local policy there are some other design tactics that you can employ to maximise the size of your new home. As most calculations are based on volume, including the void in the roof, it makes a lot of sense to design the house so that the roof space can be fully occupied.

Basements are another excellent way to add an extra storey. In most instances the volume of a basement will not be calculated as part of the volume allowance, on the basis that it does not impact on the setting. In the greenbelt, however, this may not be the case if the basement adds extra accommodation — especially bedrooms. It can therefore pay to show basement space as storage space, and to change the use at a later stage — which does not require planning permission. You must, however, make sure your design meets the building regulations for whatever purpose you eventually intend to use it for.

It is also important to have an accurate calculation of the volume of the existing building, and to argue the case for any attached outbuildings or garages within 4m of the building to be included.

Another solution is to phase your planning applications, gaining as much as is possible on a first application, and then applying for a carefully designed extension or loft conversion at a later date. It can be harder for planning authorities to find reasonable grounds for refusal of smaller individual applications.

LEFT: Paul and Beverley Wickings’ new house measures 343m2 on a plot that had permission for a replacement bungalow of just 145m2. How did they do it? By using the roof space in addition to building a basement, which was upgraded to useable space in a later planning application.

"I've got no turning area!"

The Solution: If you are building on a small plot you may find that your application is refused on the grounds that there is insufficient turning area to allow vehicles to enter and leave the highway in a forwards direction, and that parking in the street is not acceptable. This could mean having to compromise the design of your new home to create sufficient external drive space, or possibly not being able to develop the site at all. A design solution that is acceptable in many situations is to incorporate a domestic car turntable. This will allow a car to be driven into its parking location, turned and driven back out into the road within the legal requirements of many local authorities. Motorised turntables are available that rotate at the touch of a button. Turntables can be designed so that you can finish the surface with the same material as the rest of the drive.

"I've got a narrow site"

The Solution: To get the most out of a very narrow plot it is necessary to design a house with a deep floorplan front to back, over several storeys. This can present a challenge when it comes to bringing in natural light, especially in a built-up area where privacy and overlooking are serious considerations in planning terms.

Using the roof space is almost a prerequisite, and in an urban situation it will also be worth considering a basement or partial basement to add further volume. It would also be worth exploring the potential to use the full width of the plot right up to the boundaries, although most authorities will require 0.9m access for the emergency services to reach the rear of the property via an external route to one side of the dwelling.

In terms of bringing in natural light, a good solution is to design the building with large expanses of glass at the front or rear, depending on orientation and privacy issues, possibly with floor to ceiling glazing. This will in turn inform the floorplan: principal living spaces and bedrooms will tend to be located to enjoy maximum light, with bathrooms, cloakroom and secondary bedrooms where there are fewer or no windows. There are rarely opportunities to add windows to the side elevations of designs for narrow sites, and so it would be worth exploring the possibility of bringing in light from above through the otherwise potentially gloomy centre of the house, via the stairwell — albeit a narrow one. Keeping the living spaces open plan – or semi-open plan – will also help light flow through the property, create a greater sense of space, and reduce wasted circulation areas.

RIGHT: Geoff and Sarah MacCormack’s new home in West London, situated on a three metre wide infill site in a Conservation Area, maximises living accommodation with the provision of a basement and a second storey. Light is improved due to an open plan internal layout and a wall of obscured glazing to the front.

"I'm in a Conservation Area"

The Solution: A Conservation Area is defined as an area of special architectural or historic interest, the character and appearance of which it is desirable to preserve or enhance. This does not mean that if your plot is in a Conservation Area that you have to build a slavish replica of the adjacent houses. It has been successfully argued that the intention of a Conservation Area is to protect the existing buildings, but not to preserve the whole area in aspic. The word ‘enhance’ leaves the door open for new development in any architectural style, providing it can be argued that it is of significant design merit, and therefore enhances the Conservation Area. This leaves significant scope to build a well designed contemporary house within a Conservation Area.