How Long Does It Take to Drill a Hole? Typical Cutting Times and Visit Lengths

Everyone asks what size bit a soil pipe needs, but the size is the easy bit. A 110mm soil pipe through a wall usually takes a 127mm core; what more often goes wrong is the position. This guide is for plumbers, bathroom fitters, builders and homeowners adding a downstairs WC, en-suite, bathroom, kitchen sink or utility room, and covers wall and floor holes across Bristol and the South West.

Why the Position Matters More Than the Size

A hole can be the right diameter and still leave you with a pipe that cannot fall back to the WC, lands on a lintel or joist, or crosses the DPC. Mark the route from the pan connector inside, then check where it meets the outside wall before drilling.

For example, a hole marked from outside to suit a neat-looking pipe route may sit too high when checked against the pan outlet. The pipe then cannot run down to the WC as planned, and the fix may mean moving the hole, making good the wall and altering the pipework. LAP Diamond Drilling provides diamond core drilling across Bristol and the South West; the key is agreeing the centre and angle before the core bit starts.

Soil and Waste Pipe Core Sizes at a Glance

A core bit is chosen to suit the pipe and installation, not just the nominal pipe size. For other pipe sizes and more detail, see our core hole size guide before marking the wall.

What Goes Wrong With Soil Pipe Holes

Getting the Fall Wrong

The fall decides the height: a soil pipe needs a steady gradient from the WC towards the stack or drain. The hole height is set by the pan outlet and the length of the run, not by where the pipe looks tidy on the outside.

For example, if the route from the pan connector to the external wall is 1m, even a small error in the marked outlet height can leave the pipe level or rising rather than falling towards the drain. Work back from the outlet and mark the centre on the inside before transferring the position through the wall.

Lintels, Joists and the DPC

The wall can conceal a lintel above a door or window, while joists, cavity trays, wall ties and the DPC can occupy the proposed route. A hole through a lintel or below the DPC can cause structural or damp problems far greater than the inconvenience of changing the pipe route.

For example, a proposed hole directly above a window may line up with its lintel, even though the outside face looks clear. Check the structure and both sides of the wall first; never drill a lintel, beam or other structural member, or below the DPC, without proper assessment.

Cavity Walls and Drilling Straight

On a cavity wall, the inner and outer leaves may be 300mm apart. Marking the opening on only one face and drilling freehand at an angle can leave the exit 50–100mm away from the intended point on the other side.

For example, a hole that starts clear of a window reveal inside can emerge close to the outer frame or an air brick. Check the proposed centre on both faces and use a level, suitable support and the right drilling method to keep the core bit on line.

Holes Down Through Floors and Slabs

A soil pipe through a concrete floor or ground slab needs a check below the surface as well as a mark above it. Rebar, underfloor heating and the joist or beam layout below can affect the route, and a rig-mounted core drill helps keep a vertical hole plumb.

For example, a floor mark may appear clear but land over underfloor heating or reinforcement once the slab is checked. Confirm the route and scan for services before drilling; for background on the method, see this guide to core drilling through reinforced concrete.

Clearing Windows, Air Bricks and Drains Outside

The outside route needs to clear windows, air bricks and downpipes, then connect sensibly to the stack, gully or existing drain. A hole placed without checking the drain position can force awkward bends or leave the pipe with no practical connection.

For example, a soil pipe may exit beneath an air brick or too far from the gully for a straightforward run. Trace the full route outside before drilling, including the connection point and any obstacles that could interfere with the pipe or its fall.

When the Size Really Is the Main Question

There are jobs where size deserves close attention. A hole that is too tight can leave no working room for the pipe, its fall or the seal; small 32mm and 40mm waste pipes are often accommodated by a 52mm core, while the actual pipe and fitting should still be checked.

Drainage through a foundation has a separate clearance requirement: allow roughly 50mm all round, or use rocker pipes, in line with the relevant drainage guidance. Check the project details against Building Regulations Approved Document H before work starts. Here, the core size and available clearance really are central to the decision.

How to Mark a Soil Pipe Hole

1. Start inside. Mark the centre of the pan connector or waste outlet and the route from it to the wall.
2. Work out the fall. Set the wall-hole height from the outlet and the length of the run, so the pipe falls towards the stack or drain.
3. Check both faces. Look for lintels, joists, the DPC, cavity trays, windows, air bricks and the drain position outside. Check the wall type, including whether it is solid brick, a cavity wall, blockwork, Bath stone or Pennant stone.
4. Send the details. Share photos of both sides with the centre marked, plus the pipe size, wall type and any known thickness or access restrictions. LAP can review the position and confirm the drilling plan before quoting.
5. Agree the drilling method. On the day, the team checks for services and drills from the agreed face with the core drill kept level or plumb as required. LAP uses wet diamond core drilling with water collection, handheld and rig-mounted core drills, and seals the cavity where needed as part of the agreed work.

LAP Diamond Drilling is a Drilling and Sawing Association member, with CSCS, IPAF and PASMA credentials. The team has completed more than 120 jobs, from single soil pipe holes to commercial M&E work at sites including Bristol Airport and a Skanska project. LAP has a 5.0 rating from 19 Google reviews and offers free quotes from photos.

What It Costs

LAP’s minimum visit is £150, with extra holes typically £25–£150 each depending on size and material; prices are ex VAT. Grouping several holes into one visit can be more economical than booking separate visits, particularly for a bathroom or kitchen project with soil and waste pipe penetrations. See our diamond drilling cost guide for more detail.

The time on site depends on the material, wall thickness, access, service locations and water collection. These are planning estimates, not guaranteed durations; a job with 10 or more holes through mixed commercial materials may take a full day. See typical core drilling cutting times and visit lengths when planning access and trades.

Core Drilling for Soil Pipes FAQs

What size hole do I need for a 110mm soil pipe?

A 110mm soil pipe through a wall usually takes a 127mm core. Confirm the fitting, wall build-up and sealing detail before the hole is marked.

Can you core drill through a cavity wall?

Yes, provided the position and angle are checked across both leaves and the cavity is dealt with appropriately. A cavity can be 300mm across, so marking both faces helps avoid an exit that is 50–100mm out of line.

Can you drill through a lintel?

Do not core through a lintel, beam or other structural member without a proper structural assessment and approval. Move the proposed route or seek advice before drilling if the opening appears to intersect one.

How high should the hole be?

Set the hole height from the pan connector or waste outlet and the fall required over the pipe run. Check the route on the inside first, then verify the position against the outside obstacles and connection point.

Can you core drill down through a concrete floor?

Yes, but first check for reinforcement, underfloor heating, services and the joist or beam layout below. A rig-mounted core drill can keep the hole plumb where the access and setup allow.

Do you seal around a soil pipe hole?

The gap should be finished to suit the wall construction and the pipe installation, including the cavity where relevant. Agree the sealing detail before drilling, especially where the opening passes through a cavity wall or foundation.

How long does a soil pipe hole take to drill?

The cutting time and visit length depend on wall thickness, material, access, services and water collection, so a photo-based quote helps set expectations. For broader planning information, see how long drilling a hole can take.

Do I need to be there when the hole is drilled?

Someone should be available to confirm the agreed centre and access, unless those details have already been settled with the installer. Send clear photos of both sides with the centre marked so the position can be reviewed before the visit.

The size is usually the easy part; marking the soil pipe hole from the pan connector and checking the route is what gets it in the right place first time. Send photos of both sides with the centre marked to LAP Diamond Drilling for a free quote, along with the pipe size and wall type.