The block went up in 1968. What it drains into is older than that

The flat boom here is unusually well dated. The first block of flats went up in 1962, and by 1979 close to two hundred blocks lined the main roads around the village. Each one stands across three or four of the old house lots at a time, replacing detached houses and bush.

That is a nice piece of local history and it has a very practical consequence. A walk-up here was not built on a clean sheet. Those amalgamated lots already carried three or four houses' worth of drainage, and the age of the building tells you very little about the age of what it discharges into.

The short answer

Each block was built over ground that already had drainage in it. Some of that was reused because a workable connection was cheaper than a new one, some was abandoned where it lay, and some was simply built over. Almost none of it was drawn. So a plan can be entirely accurate about the new work and silent about half of what is actually down there.

1. Do not assume the drainage is as new as the building
2. Expect the plan to describe the new work rather than everything present
3. A camera shows what is there; a diagram shows what somebody intended
4. Legacy junctions sited for a 1955 cottage are where things catch
5. House-era stormwater lines sometimes still carry water under the block

On this page

1. Built over, not on
2. The records are the weak point
3. Where things catch
4. Film it once
5. What it changes about a quote
6. What we cannot do

1. Built over ground, not on a clean site

When a developer amalgamated three or four house lots in the 1960s and put a block of flats across them, the houses came down. What was under the houses largely did not.

Drainage, stormwater and service runs threading across those lots were already in the ground and already working. Some of it was reused, because connecting to a functioning line was cheaper and simpler than creating a new one. Some was abandoned in place, because removing a buried pipe achieves nothing. And some was simply built over.

None of that was careless. It was the sensible economics of the time, and it is why the ground under one of these blocks has a history that the building above it does not share.

2. The records are the weak point, not the pipework

Amalgamating lots and building over them in the 1960s did not produce a tidy set of as-builts, and what was left in the ground was rarely drawn at all.

So a plan for one of these buildings can be perfectly accurate and still be missing half the story. It describes what was installed for the block. It says nothing about redundant house-era runs, junctions in odd places, or a stormwater line that predates everything.

That matters because a confident quote given off a diagram is a quote given off a document that may describe only part of the system. It is not dishonesty, it is working from the only paper available.

3. Where things actually catch

• Legacy junctions. A bend or a junction sited perfectly for a cottage that stood on that spot in 1955 makes no sense under the building above it now. Those shapes are exactly what a newer plan will not show, and they are where material collects.
• Reused connections. Sound when they were reused and now several decades older again.
• House-era stormwater. Lines laid for cottages that no longer exist are sometimes still taking water under a building designed around a different arrangement. When a blockage does not behave like a sewer blockage, that is frequently why.
• Abandoned runs. Not a problem in themselves, and a genuine source of confusion when somebody finds one and assumes it is live.

The common thread is that all four are invisible on paper and obvious on camera, which is the whole argument for looking.

4. Film it once, and the building stops guessing

This is the single most useful thing a building of this type can do, and most of them have never done it.

A camera survey of the drainage produces something these blocks have not had since they were built: an accurate picture of what is actually under them. Where the lines run, what condition they are in, what is live and what is abandoned, and where the awkward legacy shapes are.

After that, every future decision is made from evidence rather than from a plan that was never complete. A blockage becomes a targeted job instead of an exploratory one, and a recurring problem can be diagnosed rather than cleared again.

It is also the honest limit of what we can offer. We cannot produce a historical plan that was never drawn. We can film what is there and hand over the footage, which for most of these buildings is more than anyone has had since 1968.

5. What it should change about a quote

Two things, and both are reasonable to ask about.

First, whether the quote is based on a camera or on a plan. On a building of this type those can be quite different things, and a plumber who has looked will say so.

Second, what happens if what is found differs from what was assumed. On ground with an undocumented history that is not a remote possibility, and a quote that has thought about it is more trustworthy than one that has not.

It also argues for the time spent looking being the plumber's cost rather than the building's. Finding out what is down there is part of doing the job properly here, not an extra.

6. The honest limit

We cannot tell you what was there in 1955, and we cannot produce a set of drawings that nobody ever made. Anybody claiming to know the history of a particular block's ground without evidence is inventing it.

What we can do is establish what is physically present now, show you rather than describe it, and repair what needs repairing on the basis of that. On these buildings that is a genuinely useful thing rather than a consolation prize.

And it is worth keeping. Footage handed to a building becomes the record it never had, and it is worth considerably more to the next owner or committee than it costs to obtain.

The short version

• The first block of flats here went up in 1962, and by 1979 there were close to two hundred.
• Each stands across three or four old house lots whose drainage was already in the ground.
• Some was reused, some abandoned in place, some built over, and almost none of it drawn.
• A plan can be accurate about the new work and silent about half of what is there.
• Legacy junctions and house-era stormwater are where things catch, and they are invisible on paper.
• Film it once. It is the record the building has not had since it was built.