Drainage Report

andrew_m_2

Hello,

Myself and my girlfriend are in the process of buying a house. It's a 3 bedroom 1900 mid terrace house. The survey highlighted 'right to left rotational movement of the rear two story annexe, consistent with minor settlement of the foundations'. There is cracking in the internal plasterwork and the external render. The surveyor has recommended a drainage report to be done, and here is where the problem arises.

There is no manhole access on the property. How is a drainage report normally carried out in this situation? I have been told there should be an access point somewhere and it should be possible to carry out the survey from there. A drainage company came round and said they didn't think it would be possible to do this though and the two options were to try through the soil pipe, and if that was not possible to excavate.

Any help is much appreciated.

courtjester

Older properties like this often have the original accesses cemented, built or gardened over. If there is no obvious way in visible, the only option will be to break in.

However, from what you say, this is likely to require more than just a drain survey - the vendor really needs to involve their building insurers who wil probably require trial excavation of the foundation around the area to reveal depth of found, presence and condition of drains, soil type and conditions, presence of tree roots etc. Although leaking /broken drains are a common cause of foundation movement, it is by no means definite until fully investigated.

If it is not drains, then the building has a serious problem with potential future subsidence.

This is a matter for the current vendors and their insurers to sort out - it may be quite drawn out and you should not consider purchasing until the situation is fully established and a plan instigated to implement a solution and guarantee.

Frankly, I don't see how you would proceed with a purchase with such a serious potential issue.

tali

i had a drainage report done - waste of time ,it is nothing physical at all - all i got was incomprehensible a map of various drainager /sewerage points

clutton_2

many victorian and edwardian terraces were built without inspection hatches. As it is a terrace, have a stroll down the back and look and see if any of your neighbours have had hatches installed, if they have, at least you will now know where the sewer runs (often parallel with the back of the houses). Chat to them, asking them what problems if any they had. Installing an inspection hatch is not a big job at all, providing you can locate the sewer.

andrew_m_2

Thanks for the replies. The surveyor seemed happy that the cracking was due to natural settlement, he recommended the drainage survey as any damage to the drainage may have contributed to the movement, rather than caused it.

The seller is now checking with his insurance company, so it looks like a long wait and possibly a failed purchase.

courtjester

Whoa, take care here.

"Natural settlement" ??

Buildings don't start cracking as part of their design, there is nothing 'natural' about cracking to external render and internal plasterwork - you initially reported the surveyor as talking about "left to right rotational movement" of the back addition - that is NOT natural and should not be happening.

Distortion and very long term settlement in older (Victorian) buildings is common, but there really should be no major cracks occurring - the fact that the surveyor suggests having the drains inspected reveals that he/she believes the movement is RECENT in which case, there is a *serious* problem.

Don't be misled by soft words like 'natural'.

Also, understand the clear difference between settlement and subsidence, often confused.

Settlement is compression of the building down on to its foundation (which is designed not to move) - normally and naturally occurring in modern builds whilst the building loads are taken up.

Subsidence is movement of the ground BELOW the foundation, which of course takes everything else with it.

******

The use of the word settlement is often used to describe very gradual and long term subsidence in older buildings which results in 'character', but if not progressive or sudden /recent is accepted as natural. Does not normally involve opening up of cracks as the building materials tend to be flexible enough to absorb the minute long-term structural change.

Cracks occur where movement is either too quick /sudden for the building to absorb naturally, or there is differential movement between parts of the building due to different forces on the respective foundations below those parts, or due to external causes introduced after the construction - such as the effects of broken drains, tree roots, gorund water, seasonal drought etc.