Groundwork and drainage in Woolwich: foundations, drainage runs, soakaways, patios and hardstanding. The part of a build nobody sees and everything sits on.
Because it is dug, carted away, inspected and filled with concrete, and none of that is visible when it is finished. It is the part of a build most often underquoted and the part that cannot be revisited later.
Building Control inspects the trench before concrete goes in - that is a required stage, not an optional one. We book it and we do not pour until it has happened.
Yes, and it is a common cause of it. A patio laid above the damp proof course, or falling toward the house, puts water where the wall cannot shed it. We set the levels to avoid exactly that.
For a single-storey extension, digging, inspection and concreting the foundations is usually one to two weeks, depending on the depth needed and the weather. Drainage alterations add to that if a run has to be moved.
Sometimes, but a sewer shared by more than one property usually belongs to the water company, and building over or near it needs their agreement. It is checked early because it can change where an extension can go.
Groundwork is the least visible money on any building job and the least forgiving. A foundation to the wrong depth or a drain run with the wrong fall cannot be corrected once there is a building on top of it, which is why it is the first thing we get right rather than the first thing squeezed.
Ground conditions change quickly across Woolwich and Plumstead. Clay on the higher ground toward Shooters Hill moves with the seasons and with nearby trees, and needs deeper foundations than the lower ground nearer the river. That is why foundation depth is set by what the trench shows and what Building Control agrees, not by a standard figure.
Dug and inspected to what the ground actually requires, not to what makes the quote look good.
A drain with too little fall blocks and one with too much leaves solids behind. Both are expensive to revisit under a slab.
Where the water goes matters as much as where the building sits, and it is increasingly what Building Control asks about.
Laid to fall away from the house, on a proper base, so they do not sink or send water at the wall.
On clay, a tree near a new extension affects how deep the foundations go. Its species and distance are checked at the design stage, not on the day the trench is dug.
Victorian drains under Woolwich terraces are often cracked or shared between houses. A camera survey shows what is there before anything is built over it.
Send a photo or a quick video of the room on WhatsApp, or get a free fixed quote, no obligation, and we’ll tell you straight what it needs.