How to design a drive

With drives, probably more than any other thing in gardens, the most important thing is it actually functions as it is intended. No matter how nice it may look, if it does work as a drive it is a waste of money. As ever there has to be some compromises, for example: you may what a turning circle in your drive but they need an awful lot of space. To start with you need to decide how many vehicles you are going to what to park on the drive and do you need to be able to pull onto the drive, turn around and then drive back out. You also need to consider how often individual vehicles will be needed, ideally you are not going to want to be constantly moving vehicles around just to get one particular one out. Last but not least you need to consider access to garages and house doors and how much of your garden you want to make into the drive.

Now look at what space you’ve got. An average car needs a space of 2.4 metres by 4.8 metres to park on and this doesn’t include space for manoeuvring it. Make a sketch and some vehicle sized pieces of card and try moving them about on the sketch, allowing for how they are going to swing out when turning. At this point you are going to have to make some compromises so consider what is important. Once you feel comfortable with the layout of your drive mark it out in the garden as you plan to have it and actually try it out. It is far easier to change now than later. To help I’ve includes some dimensions that may be helpful at the end.

You are almost ready to construct your drive but before you start checking the cost of materials it is important to consider if planning permission is needed. The pressure for off road parking has led to more and more gardens being paved over and while this does get cars off the sides of roads it means the rain that would soak into the front gardens now runs off them. The amount of rainwater running off a car parking space in a front garden may not seem much but once this is multiplied up for a town, never mind a city, it amounts to a lot of additional water going into drains and ditches. In response to this the government decided to bring in planning controls to cover non-porous paving in front gardens. What this boils down to is that any water that falls onto you drive you need to get rid of on your property and not down the drains. In many cases this can be as simple as providing adequate areas of borders for the water to soak into naturally, but where this is not an option either a permeable surface has to be used or the water has to be collected into drains and lead to a soak away where it can then seep away into the soil. Further details can be found on the government’s planning portal here. Planning rules are complex and special rules can apply in many situations so a 5 minute phone call to your local planning office at this point can save a great deal of trouble later. Whatever you do don’t try to emulate the Ostrich!

Drive surfaces

No drive surface is perfect and they all have their strengths and weaknesses so you have to decide which compromise is going to work for you.

Block paving

Block Paving

Block paving laid in a pattern using different colours

Pros:

  • Easily forms curved shapes
  • Adapts well to changing slopes
  • Sections can be taken up and re-laid to gain access to buried services
  • Vast range of finishes
  • Some designs are now permeable.

Cons:

  • Not suitable for poorly drained ground. The sand bedding course must be well drained and at least 600 mm above the water table.
  • The edges must be well retrained
  • Prone to sink where car wheels continually run
  • The more ornate finishes can be expensive.

Flags

Pros:

  • Can be very cost effective

Cons:

  • Only the 50mm thick flags are suitable

Grass concrete composite

(Concrete blocks with grass growing through gaps mounded in them)

Pro:

  • Simplify the job of getting rid of surface water

Cons:

  • The grass will not withstand heavy use
  • The grass will not survive under vehicles park continuously over it
  • Take time to establish
  • If the grass cover breaks down it will quickly become muddy.

Gravel

Pros:

  • Adapts to any shape
  • Cheap
  • Self-draining

Cons:

  • Only suitable for relatively level areas
  • Weeds quickly establish in the areas that aren’t been driven over
  • Moves about
  • Cannot be laid onto a hard surface such as existing concrete

Hardcore

Pros:

  • Cheap

Cons:

  • Easily eroded by water running down it
  • Not all hardcore is suitable

 

Pattern Impressed concrete

Pros:

  • Weed free
  • Large range of finishes available

Cons:

  • Must be laid by a good specialist contractor
  • With use the parts receiving concentrated wheel traffic start to fade
  • Very difficult to repair successfully

 Plain concrete

Pros:

  • Weed free
  • Relatively cheap

Cons:

  • Unattractive appearance
  • Needs to be well constructed if it is to last
  • Difficult to repair

Pointed setts

Granite setts

Pointed granite setts

Pros:

  • Combination of small paving units set in pointing makes an attractive finish
  • Adapts to complex shapes
  • Suitable for slopes

Cons:

  • Very expensive
  • Requires a lot of skill to lay

Resin bonded aggregates

Pro:

  • Less prone to move about than gravel
  • Available in a range of attractive finishes

Cons:

  • Not suitable where it is likely to become contaminated with mud
  • More expensive than plain gravel

Tarmac

Pro:

  • Adapts to complex shapes and slopes
  • A good compromise between cost and length of service
  • Well suited to large drives and heavily used ones
  • Available in a range of colours

Cons:

  • Has to be laid by a good specialist contractor
  • Colours only available subject to suitable plant near by

 

Drive dimensions.

These are for guidance only and should be checked before being used.

  • Local regulations and restrictions may apply and you should check before starting any work.
  • The drive entrance should only be at the verge crossing.
    • The verge crossing will have lowered curbs for the vehicles to get onto the road.
    • New or changed verge crossings will normally require permission from the council highways and planning departments.
    • Verge crossings must be constructed to special specifications.
    • Verge crossings must be constructed by approved contractors.
  • Ideally a drive should be 3.2 metres wide (or 2.6 metres if there is a separate footpath).
  • If you are putting gates on a drive opening onto a busy drive you may have to set them back 5 metres from the edge of the highway to allow a vehicle to pull safely off the road before needing the gates opening.
  • Check you can see clearly from the car driving seat when you pull out of the driveway.
  • Any water on the drive must not drain onto the highway, but must be disposed of on site.
  • Long drives need special considerations.
    • Bends need to be wider to allow vehicles to turn.
    • Oil delivery vehicles may only have 30 metre long delivery hoses.
    • Oil delivery vehicles are typically 7.2 metres long by 2.6 metres wide and weigh 18 tonnes.
    • LPG delivery vehicles need to get to within 25 metres of the fill valve.
    • The fire brigade need to get their vehicles to within 45 metres of the house.
Model Drive

Model Drive

Model drive turning circle

Model drive turning circle

Liz McNee, Mark McNee liked this post

Garden Myths: Number 14

It’s a dwarf conifer!

Gardens are littered with 6 metre high conifers with a small group of rocks around its base. Invariably this is the last resting place of a garden rockery with a dwarf conifer planted in it. For some reason people have no problem with seeing an oak seeding will grow into a tree but when looking at a small conifer plant they think it will stay small. There are in fact only a couple of truly dwarf conifers and they are not very common, all the rest are little conifers which just haven’t grown yet.

Garden Myths: Number 13

Lawns are less work than borders.

No, but they take less thought on the part of the reluctant garden. Just think about the time you spend following the lawn mower up and down the garden every year. Now compare this to how much time you spend looking after an established border of similar area. Initially the border does take more time, effort and thought; but once established it should take a fraction of the time the lawn does.

Garden Myths: Number 10

Plants will go to a particular size and stop.

People often ask for plants to do things that are not realistic and the commonest one is for a plant that will grow to a particular size and stop. That is understandable but sadly some people in the horticultural industry will actually tell them a particular plant will do just that. Providing such action is wholly unprofessional and reprehensible.

All plants will grow at different rates throughout their life and ultimately there growth will slow down a lot, but this can be when they are centuries old. Clearly some plants will always outgrow others but their growth is strongly influenced by the conditions they are grown in. To take an extreme example take an oak tree in open parkland and grown as a bonsai.

Garden Myths: Number 8

Waterfalls and streams need a mains water supply.

The first time, on discussing creating a garden pond, the customer carefully explained where the mains water supply was “as I would need it” I was taken aback; but it has happened now a number of times. The logic I presume is that as there is water running it must be from the mains. To clear up any confusion the water is circulated by an electric pump. Using the water mains wouldn’t work for a number of reasons. Tap water contains chemicals such as chlorine and fluorine which are added that could harm the plants and fish, if you’re constantly adding more and more water from the mains where will the excess go to, what is your water bill going to be, what happens as the water pressure goes up and down, what’s going to happen to the water pressure in the house and a domestic water supply does have sufficient water pressure or flow rate for all but the smallest water feature.

Garden Myths: Number 3

Garden ponds need a filter.

Properly designed and planted a garden pond does not need a filter. Long ago when I was a child we had a garden pond, along with many other people of course, but no one had a filter on them. This was for a good reason; they didn’t exist for garden ponds. What changed things was when people in this country discovered the hobby of keeping Koi fish. These fish are large, colourful, expensive thugs that dig up any plants growing in the pond. This meant people wanted ponds with just the fish in them but the fish could not survive in these conditions so Koi keepers invented the pond filter. This allowed pond water to be artificially kept very clear so people quickly realised it was easier to fit one of these to the pond to get clear water without the fuss of making sure the pond was properly planted up.

Succulents Simplified by Debra Lee Baldwin

First off I was kindly lent a review copy of this book by the publishers Timber Press.

Its is clear from the book that Debra is a very knowledge and experienced grower of a group of plants which is often overlooked by UK gardeners, but non the less a very useful one. She does fall into the trap of all specialist plant books of seeing the subject of her interest as the solution to a gardens wants; but still finds many interesting and original uses of succulents.

The book is very richly illustrated with some mouthwatering plants and interested uses making it a useful reference book. The only real drawback is that the author is living and gardening in southern California where she enjoys a far milder climate that the UK, or for that matter most of America. This means a large majority of the plants are only going to be suitable as house-plants for most of us.

 

Bond, English

This is one of the commonest method of constructing a brick wall which is more than ½ a brick thick and consists of alternating courses of heads and stretchers.

English bond brickwork

English bond brickwork

The minor wall building materials

Metal

Though important in building is garden use is rather limited but can if used carefully can be very effective. The term metal encompasses a vast range of material, many used since ancient times, and the suitability of a particular one will depend on the individual use planned.

Reinforced concrete

This material combines concrete and steel to create a material with excellent compressive and tensile strength. This provides the potential to provide some very graceful and elegant structures but the complex nature of the material means is design and specification requires specialist expert knowledge.

Concrete reinforcing should not be confused with crack control in concrete, by weldmesh or polypropylene fibres, which serves a very different purpose.

Plastic

Traditional plastic has not been used a great deal in garden construction but the vast range of different forms of plastics means it has great potential. It has the advantage that it is very rot resistant, can be moulded (and some can be machined), pre-coloured and even some is made from recycled materials means it is beginning to be used for more than pond liners and roofing sheets.

Glass

Used for hundreds of years, recent developments in glass technology means this is a material with great future potential.

Peat blocks

Traditionally these have been used to make raised peat beds, but have they have fallen out of favour in recent years as a result of the environmental concerns around peat harvesting and use.

Peat block wall

Peat block wall

The main wall building materials

Brick

Reclaimed brick walling

Reclaimed brick walling

One of the oldest and most durable building materials; its variability, flexibility, durability and strength has made a ubiquitous walling material. Traditionally made from dried earth the centuries of use and development has lead to a very sophisticated produce now mass produced in millions each year in the UK alone.

The earliest bricks were probably made of mud and date back at least 5000 years, and probably considerably more. Modern bricks are still normally made from fired clay (a natural extension of sun-baked mud) but they now come in a vast range of colours and surface finishes. It must be remembered that most facing bricks, while very strong are damaged by frost if their exposed surfaces are saturated with water. The only real exception to this is engineering bricks which are not as absorbent as facing bricks, but are only available in plain red or blue.

 Concrete

The use of concrete dates back at least 2000 years; it was used extensively by the Romans and there are Roman writings on its mixing, placing and use. Though its use has waxed and waned with changing fashions is seems every new generation re-discovers it, finding original uses for it.

Years of use and study have meant that what may appear to be a very simple basic material has become a very complex subject. What is frequently not appreciated is concrete, while having excellent compressive strength1, has so little tensile strength2 that is it regarded by engineers as having none.

Stone

The stone mason is one of the oldest trades and stone walls have been found wherever stones can be sourced. The earliest were probably dry stone walls built from stones found laid on or near the surface of the soil.  The durability and effective ness of these can be seen from the miles of dry stone wall which snake over the North Yorkshire Dales, where the shallow topsoil means the stones could be sourced by gradually picking up stones laid about the fields. Once metal tools had been invented stone could be cut, worked and polished allowing the creation of the pyramids and temples of the ancient world.

Wall detail at Dornoch Cathedral

Wall detail at Dornoch Cathedral

Stone comes in a vast range of forms and this determines it suitability for building and what results can be achieved. As one of the main costs of stone is haulage, traditionally it was sourced close to where it was to be used so lending distinctive local styles to walls.

 

Timber

Though not as durable as stone or brick, its easy of working and availability has meant it has long been used as a building material. It has also has other advantages over brick and stone work: it is a lot lighter, possesses tensile strength2, can be readily coloured with stains and paints, and although it does weather it is unaffected by frost.

Timber pole walling

Timber pole walling

Wood is though a very variable materials depending mainly on the tree species it comes from, but also the environment the tree grew in and the part of the tree it is harvested from. When used in construction this can lead to concerns about its structural strength and for this purpose it is “stress graded” but in a garden context the size of the timbers chosen for aesthetic considerations means this is unlikely to be important.

Notes:

1)      Compressive strength is simply the ability of a material to resist being crushed.

2)      Tensile strength is simply the ability of a material to resist being pulled apart, something that brick, concrete and stone walls actually lack. Hence the need for arches or solid lintels over openings in walls.