This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol3", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
Sometimes, when land is excavated, matter oozes or flows into the excavation, which is of such consistence and composition that it is by no means easy to decide whether it should rather be considered as wet earthy or rocky matter, or as water carrying mineral particles in suspension. As above stated, it is prima facie quite lawful for an owner of land to drain stagnant water from his own land, whether at the surface or below it, and he may sink wells and use pumps to fetch up the water ; and if his neighbour's land suffers from removal of water support by such means he is not liable for the injury inflicted. There may easily arise cases from time to time where so much solid material, mixed with, or suspended or dissolved in water, will be displaced from beneath one tenement and carried away towards excavations in a neighbouring tenement, that surface damage may result for which the person excavating might be held legally responsible.
The questions for decision in such cases are for the most part questions of fact, but they may be facts of such an uncertain character that it may be very difficult, indeed, to arrive at a final and just conclusion concerning them.
A right to adjacent support must not be taken to be limited to land immediately adjacent so as to exclude the liability of owners of more distant tenements, when excavations on those distant tenements can be proved to have caused the injury complained of. Theoretically, there is no limit of distance, and the existence of intermediate tenements is no bar to a claim for damages for removal of support if the facts are such that the damage inflicted has clearly resulted from acts done by a distant owner or occupier upon his land. In some cases excavation may really cause injury at a distance, while in other cases excavation, such as quarrying solid rock, for example, may be carried on quite close up to the limits of a neighbour's land without danger of inflicting injury within his borders.
When actual subsidence of a surface has taken place, and it is alleged by the owner to be due to the acts of a neighbour who has removed support to an actionable extent, it may sometimes be shown that the owner of the damaged tenement has weakened his surface by excavating on his own land ; and if it should appear that he has contributed towards the effect finally produced by this or other means, the neighbour will not be responsible merely because he also has contributed to diminish the support, and thus ultimately caused the subsidence. In such cases the owner complaining of injury must show not merely that neighbouring excavations have caused the subsidence on his land, but that they would any way have produced the same result if his land had been in its original natural condition ; or else it must appear that he has acquired an easement right, binding upon his neighbour as a servient owner, to leave an additional amount of support sufficient to counterpoise or compensate for the increased weakness of his surface. Otherwise the neighbour will not be held legally responsible for the damage, because in excavating on his own land he is prima facie acting within his own natural rights, which are only limited by, and coterminous with, the natural right of his neighbour for support sufficient for his land in its natural unweakened condition.
The same principle applies where heavy buildings have been erected upon land. Neighbours are not prima facie liable to provide any extra support for the buildings, nor are they bound to abstain from excavating or otherwise dealing with their lands as they might have done before the buildings were erected.
Their rights are the same after as before the erection of the buildings, and are limited to a legal obligation to leave sufficient support for the land, such as it was before the buildings were placed upon it. The person who has erected the heavy buildings could not place increased burthens, or impose increased restraint on neighbouring owners or occupiers without their consent ; neither could the neighbours repudiate or otherwise get rid of their obligation to respect the natural right of support for the land built over.
A right to additional support for houses could only be acquired as an easement by one or other of the means by which such easements can be brought into existence. Until an easement has been acquired there is no obligation for any neighbour to contribute in any way towards the support of the house apart from the land it stands on, which is entitled by natural right to have sufficient support for itself alone, as if it were still unweighted.
When, therefore, a house suffers damage as a consequence of removal of support by a neighbouring owner or occupier, it is important to know or ascertain in each case whether an easement of support exists which is binding upon that neighbour as servient occupier of a servient tenement. If such easement exists, and the house is damaged as a consequence of illegal removal of support by a servient owner, that person is liable for the damage ; but if no easement were in existence the neighbour removing support would not ordinarily be responsible unless he had failed to leave sufficient support for the land in its original vacant condition.
Sometimes buildings are supported (in part at least) by other buildings, and rights of easement for such support may be acquired ; but in the absence of an easement the owner of a building is not ordinarily under obligation to afford continued lateral support for buildings close to his own. He is not under any legal obligation to consult his next-door neighbours before pulling down his house, nor to shore up the walls of adjacent houses when he pulls down his; but he must, of course, take care that in pulling down his house he does not damage the property of his neighbour.
This obligation, binding upon every man to take care that he does not injure his neighbour while looking after his own interests (sic utere tuo ut aliemim non Iaedas), is of particular application to the case of closely adjacent houses, where, by want of care in effecting structural alterations, more or less serious injury might be easily inflicted upon neighbours and their property ; but neighbourly consideration and the special carefulness which special circumstances may require are matters apart from the law of easements. The owner who wishes to pull down his house, where no easement of lateral support for a neighbour's house exists, is not under obligation to abstain from the exercise of any or all his natural rights arising out of the ownership of his house. He is only bound to be careful as to the way in which he exercises his rights.