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The Essential Guide » Finding & Buying Land / Property » Will the Land For Sale Be Suitable For Our Self Build Development Project?

How do we know that a Building Plot will be suitable for our Self Build Development?

Generally, these days we can build just about anywhere.

For centuries, new properties have been built on rivers, boggy marshes, running sand, rock, and even in earthquake areas. house on stilts

What is the more important factor to consider is “How much will it cost to build on a specific parcel of land”?

You may find what you, at first glance think is “the perfect plot”, but when you get to learn a bit more about it, you find that there may be factors linked to either the condition of the ground itself, or maybe to access to the site, availability of services, - or even to obtaining Planning Permission which will have negative effects on the “viability” of the plot as a potential place to build your new home.

Any inherent problems, whether they be to do with the nature of the land itself, its location, Planning Permission or whatever, all tend to have the effect of increasing the overall cost of the project.

So, an important question which you need to answer, before you commit to purchasing any land for a potential project, is:

**“Will the cost to overcome any problems associated with anything to do with the land, have the effect of making the project unrealistic financially?”**

In this section we will look at some examples of problems which are often encountered when developing a site, and briefly outline potential solutions.

It would then be up to you as individuals to decide whether your particular project a “viable proposition”.

This list is, however in no way exhaustive. Each site comes with its own “unique” characteristics, and sometime you may find that as you start to look closely at a particular site, it actually has not just “one”, but a multitude of problems which, all added together will just make the whole thing “a none starter”!

You may be experienced in building, but on the other hand you may have no experience whatsoever, and be completely in the dark over recognising any potential problems. If that is the case, then you would always be recommended to take on some “professional help” such as an Architect , Planning Consultant, (possibly a Project Manager), or whoever you can find (preferably locally so they have some knowledge about “that particular area”). – Have a look in the “Trade Directory on this site – There are plenty of each one of those “Specialists” who should be able to help you.

Whether you are “going it alone” or getting help, there are areas that you should be looking out for when you first visit any plot on which you could potentially be building your new home. These include:

Ground conditions:

A simple “quick walk” around the site should start to give you an idea of how suitable it will be for your development.

Does it feel firm underfoot, or is it “mushy”.
Is there water holding on the surface anywhere? Is there any sign of rock?
Is it generally flat or sloping?
Does the ground look like sand, clay, or topsoil?
Is there any sign of “Viral” weeds?
Can you see any sign of badger sets, rabbit burrows etc? – Each different ground condition will bring with it its own set of “factors” which will affect the development.
Are there signs of contamination?

“Mushy ground”:

If you encounter “boggy”, “marshy” or “mushy” ground, it could result in you having to excavate your foundations deeper, or, in some case, take other “more extreme” measures to get down to a “bearing strata” (in other words a “firmer layer of ground) that will be able to take the weight of the development.

This may mean you have to consider a reinforced raft foundation, or even piles (details of these can be found in other sections of this guide).

“Land which is holding water”:

Water lying on the surface ( especially when it has not been raining for a while) may mean that the land has a “high water table” or drainage “issues”.

These can potentially cause problems, both with the design of the development, and with some of the more practical aspects of the project, such as, - once you start work, having to constantly “pump” the water away during the excavation work. Or the sides trenches being waterlogged and constantly “caving in” after you have finished excavating , leading to extra work “cleaning them out” and you using far more concrete than you originally envisaged.

Site drainage problems may also mean that there will be a need for you to install “land drainage” or some other form of “de watering” system, which can be expensive, and could need maintenance in the future.

“Rock”:

You may think that building on rock would be ideal.

In some ways it can be, BUT, if you have to excavate down to a certain “level” (for Building Regulations - generally about Rocky ground

900mmm ), or, if you need to remove rock to get an adequate “fall” on your drainage system, then it can cause major problems.

Some of the softer rocks can be broken out fairly easily with an excavating machine fitted with a “jackhammer” type attachment. Other harder rocks can cause big problems.

Another situation where rock can cause problems where there is “some” rock, and “some” of another type of material, (for example clay) in the vicinity of your proposed foundations.

Rock will not dry out, settle or move in the same manner as clay. This could lead to something called “differential movement” and / or “differential settlement” of the ground around the foundation. This could lead, in turn to cracking of the foundation concrete, and possibly the structure itself.

To get over this, the Building Regulations department may ask you to “reinforce” the foundations to give them extra strength where the different ground materials meet.

Unfortunately this is a problem that may not be obvious on your first “walk around the site”. It may not become apparent until you start doing some digging and you can physically see the bottom of the trench where different types of ground meet. – If you do find that you are keen on a particular plot you would be advised to ask the owner if they have had any “trial holes” dug, and tested. If they have, ask them for the results, and get them checked by your Architect / Designer to make sure they are satisfactory. – If no trial holes have been dug, ask if you can do some. – Even if that means just digging a few holes yourself with a shovel so you can at least start to get an idea of the “makeup” of the ground you could potentially be developing.

If you don’t take steps to make sure that the ground is suitable for “simple” building to take place on, you could find that you end up spending many £1,000’s later on, getting over problems that you encounter AFTER you have committed yourself to the project.

“Flat / Sloping land”:

Flat land is usually the cheapest to build on. Sloping sites can mean that you have to “Cut” and / or “Fill”.

In other words you may need to “cut” into a bank, and take the “spoil” (earth) that you remove, away from the site.

Or, you may need to build up one section of the site to bring it up to the required level. - This can mean “importing” soil or stone, and that can add significantly to the cost of the development.

The built up area of the land may then bring with it new factors to be considered at the “foundation design” stage.

Ground which has been “freshly” built up will not be fully “compacted”. This will mean that it will tend to settle over a number of years. If you built on it too soon, without taking precautions, you could end up with a house that “settles” along with the ground it’s sitting on!

Where you are planning to build on “fill”, you need to take steps to make sure that the foundations actually sit on ground which is not going to settle.

This could include you having to take re excavate through the ground you have just built up, to get down to a suitable “load bearing strata” which will be able to take the weight of the new building (this can bring with it its own problem of trench sides “caving in” due to their lack of stability). Another option would be to “pile” through the “soft ground” to reach the original (or suitable) ground.

Sand / clay / soil:

There are many types of “ground” in the UK. Each type has its own characteristics. Sometimes you get a mix of two or three types of ground in a single area. These will all have their individual impacts on the development (in just the same way as rock / softer ground can cause problems. Once you have dg your “trial holes”, your designer should be able to advise you on the implications of the “nature” of the ground. – In “many”, possibly “most” cases, the ground is suitable for building on without any major “improvement”, but you should always find out before you buy any “development land” whether or not it will be suitable.

Viral weeds:

You may not have heard of these. There are some areas of the country that have no problem with them – Yet!

However, if you find that the land has some level of “infestation”, you will either need to get rid of them altogether before you build, or take steps to treat and kill them so that they don’t cause you any problems later on.

Both “treating” and removing these weeds can be very expensive and time consuming.

If, while you are looking around the site you see some growth that is obviously not a “standard garden weed”, then you should get advice on whether or not it could cause you problems.

Badger sets / Burrows etc:

These can cause “time consuming” and expensive problems for you:

If you find a badger set on your land, you will need to notify the Planning Department and they may require that you bring in specialists to remove “sets” and the animals from the site.

If your land does not presently have Planning Permission, and there is a badger set on it, it could actually result in you not being able to get Planning Permission at all.

Once a “family” is removed, you are left with “the set”. If it happens to be under the area where you want to position the new house, you may have to dig out the ground around the set to make sure you get your foundations to a level below any “voids” in the ground. This may mean that, as well as paying for the extra excavation and possibly the removal from site of the excavated material, you also use end up using a lot more concrete, or maybe have to “shore” the sides of the trench. It all adds time and expense to the project.

On top of the ground conditions, there are other factors which can make the difference between the site being "viable" and being " a non starter" - These include:

Access:

This is something which can have just as major an impact on the development as any of the physical “site conditions”.

If you can’t get to the site easily you may end up having problems with deliveries. - You may not be able to bring roof trusses to the site, and end up having to build a traditional, “hand cut” roof (which can be a lot slower and a lot more expensive than a standard “trussed roof”.

You may need to have all deliveries made on small vehicles, or may have to “offload” some distance away from the position where the actual “building” work will be done, and you may then have to transfer everything to where it is needed, - by hand / wheelbarrow or forklift (and forklifts cost a lot of money to hire!)

You could also come across more significant “permanent” problems in relation to access if “visibility” at the entrance is poor:

To satisfy Planning requirements, you have to conform to certain rules governing access.

For example, if your neighbour’s wall restricts your view down the access road, the Planning Office may require that it be altered before you can develop the land. - If your neighbour won’t let you make the alterations to his wall, the project could be a “non starter”. – So, for something as minor as a small cosmetic change to a neighbours wall, the whole project could grind to a halt before it even gets going properly! - Again, your designer should be able to advise you on this and other similar subjects.

Existing services:

All the everyday services which we take for granted can have a huge effect on your project, even before you have started planning to build the house where you would use them!

You may “walk the site” when you first visit, and see a small manhole cover somewhere near where you would the “purchase process”. Later, however, you may find out that “innocuous” little cover is actually the main “Council drain run” which services the whole area and which cannot be moved. - You would also then probably find that you are not allowed to build within 3 metres either side of it (to allow maintenance vehicles access to it).

The effect that the drain could have on the project could actually turn out to be “terminal” if it meant you could not build a house of the size you need or position it where you need to.

The same problems can apply to water, electricity and gas mains, plus Telephone cables, both underground and over ground.

You may however find that the existing service running across your site is either disused, or can be moved without much problem, - or, in some cases, that you can actually build over it.

Where existing services are found on your site, then BEFORE YOU START WORK (and preferably before committing yourself to the project) you should contact the relevant authorities to let them know you have encountered one of their services, and to find out how they will impact your project.

The “Dial before you dig” service can be of great help here (just make an internet search on the name to find out more).

Existing buildings:

Small existing buildings can often be removed without any major problems, but bear in mind that they may have foundations which will have to be taken up. If those old footings are in the place where your new foundations need to be, they may impact on the amount of work needed to excavate the trenches, the materials and the cost of the job.

If the existing buildings are large, e.g. if you demolishing an existing house to replace it with a new one, the process can be extremely time consuming and the cost can be significant. – (There is a separate section later in this manual dealing with “Demolition”).

New services:

Main services may, if you are lucky, run right past your land, or, if you are not so lucky, they may be a significant distance away.

Find out where they all are early on. - Even if they are “just across the road”, actually bringing them onto your land could potentially cost you thousands of pounds.

Sometime one or more of the main services will not be available at all.

You need to know early on in the planning stage of the project, how this will impact on your development costs, and also potentially your “living conditions” when you actually move in:

You may need to install an oil storage tank, or gas cylinder store.

You may need to dig a well for water, or install a septic tank.

You may not be able to get a telephone line to the property.

Lack of services and extra “cost of living” because of problems with services can have a negative effect on the value of the finished property.

Planning restrictions (“building lines” / size / position / height ):

You may find that when you apply for Planning Permission, that conditions are imposed on the development, which can have sometimes have a dramatic effect on the project as a whole.

If you have to build behind a “building line” it could affect the size of the property, or the garden.

Other restrictions could mean that you can only build on one area of the land, which may restrict the size of the property you are able to build.

You may want to build a 2 storey property in order to get the accommodation you need, but may find that a height restriction can mean that you can only build a bungalow (where this happens you can sometime build a dormer bungalow – but you would have to check with your Planning Office).

Your Architect / Planning Consultant etc should be able to help you with this.

TPO’s (Tree Preservation Orders):

Quite a common problem that Self Builders have to get over is the one of TPO’s. – Trees which are protected and can’t either be removed, or in some cases even “lopped” can stop a project in its tracks in just the same way if you didn’t receive Planning Permission in the first place! – Just be wary when you look at land for the first time: If there are trees which would interfere with your proposed development, contact the Local Authority to find out if they have TPO’s on them. – If they do, you should not go too far further with any purchase process or Planning application until you know that the problem can be solved one way or another.

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