Introduction

Ever had a client point to a finished wall and say, “That’s not where we wanted the switch”? It’s common, and it hurts. A tight pre‑drywall walkthrough catches those misses while fixes are cheap. This guide shows you exactly how to run one: what to check, who to involve, and how to document decisions so they stick. You’ll get UK‑specific reference points for heights and airflow, practical checklists, and a simple way to turn your notes into an agreed action list you can track to completion.

Table of Contents

• Key Takeaways
• Plan The Walkthrough And Set Expectations
• Electrical And Low-Voltage Layout
• Plumbing, Heating And Ventilation
• Framing, Openings And Backing
• Air Sealing And Insulation Readiness
• Document, Agree And Action The List
• Frequently Asked Questions
• Conclusion

Key Takeaways

• A structured 45–60 minute walkthrough commonly saves a full day of rework later and cuts snag lists dramatically.
• Follow UK guidance where it matters: Approved Document M for switch/socket heights and Approved Document F for extract rates; reference BS 7671 for cable protection.
• Catching relocations now is cheaper: moving a socket after plasterboard is commonly 3–5 times the time and cost.
• Photograph, mark and get sign‑off the same day; many contractors find this halves back‑and‑forth and prevents “he said, she said”.
• Use voice, photos and simple PDFs to create a shared action list clients can sign electronically and you can convert to invoice later when appropriate.

Plan The Walkthrough And Set Expectations

The Problem

Walkthroughs drift when no one knows the agenda. That’s when decisions get made in corridors and then forgotten, creating changes after boarding.

The Solution

• Invite decision‑makers only: client plus designer (if involved). Keep the crew light—one lead, one fixer.
• Time it right: after first fix is complete, services pressure‑tested, and before insulation/board. Commonly, a 45–60 minute slot is enough for a 3‑bed house floor.
• Bring the right kit: plans, tape/laser, spirit level, marker, blue/red tape, step ladder, charged torch, moisture meter (for suspect studs), and a phone for photos/voice notes.
• Explain the rules up front: “We’ll mark, photograph, and agree changes now. Post‑walk changes may extend programme and cost more.” Clients appreciate clarity.

Real‑World Example

On a small kitchen extension, the client wanted under‑cabinet lights on a separate switch, but the plan showed a single gang. During the walkthrough, you confirm the preference, mark the second gang, photograph the location against a tape measure, and note: “Add 2‑gang at 1100 mm AFFL, right of patio door, feed from CU circuit B6.” That note prevents guesswork later.

Electrical And Low-Voltage Layout

The Problem

Misplaced sockets, clashes with cabinetry, and unprotected cables lead to costly rework and compliance issues.

The Solution

• Heights and locations:
  • Follow Approved Document M guidance: sockets typically at a minimum 450 mm above finished floor level (AFFL) and switches 900–1200 mm AFFL in accessible dwellings.
  • Mark final finished floor level on studs to avoid future mis‑measure.
• Protection and routes (BS 7671):
  • Cables run within prescribed safe zones or more than 50 mm from the surface; otherwise provide 30 mA RCD protection or mechanical protection (e.g., steel plates). Mark any zones that are close.
  • Fit nail plates where services pass within strike zones of fixings; many contractors aim for plates on every stud crossing as a rule of thumb.
• Count and confirm:
  • Agree every outlet: power, cooker points, isolators, appliance feeds, data, TV, speakers, EV pre‑run if applicable.
  • Confirm back box sizes (25/35 mm), especially for dimmers, smart controls, or data keystones.
• Kitchen specifics:
  • Check counter run—keep sockets clear of hob splash area; verify appliance isolation positions and depths behind planned units.

Quick Checks That Prevent Callbacks

Real‑World Example

A hallway with three doors often ends up with switches that clash with casing. You mark switch centreline 100 mm off casing edge, at 1100 mm AFFL, photo the mark with a level, and label “clear of architrave by 10 mm”. Commonly, this simple mark prevents the plasterboarder from covering the box or the carpenter from fighting the casing later.

Plumbing, Heating And Ventilation

The Problem

Misaligned pipe stubs, shallow falls, hidden valves and poorly run ventilation cause leaks, noise and mould complaints.

The Solution

• Drainage falls and traps:
  • In general, keep branch drains around 1:40 fall (about 25 mm per metre). Avoid bellies and tight bends.
  • Confirm shower and bath trap access; mark access panel positions.
• Water supplies and isolation:
  • Mark main stop tap and any zone valves so they’re accessible. Clients often want a simple shut‑off they can find in seconds.
  • Check radiator tails are centred and at consistent heights to suit the selected radiators.
• Ventilation (Approved Document F typical rates):
  • Bathrooms: 15 litres/second intermittent (or around 8 l/s continuous). Kitchens: 30 l/s intermittent (or around 13 l/s continuous). Agree fan types and routes now.
  • Ducts to discharge outside, not into lofts; insulate ducts in cold spaces to avoid condensation.
• Heating plant and cylinders:
  • Confirm service clearance and future maintenance access. Commonly, we allow a full face‑off panel width plus top/bottom clearance.

Real‑World Example

You find a bath mixed tap set 40 mm too far from the planned panel cut‑out. During the walkthrough, you re‑mark centreline, take a photo with a tape, and record: “Shift bath mixer supplies 40 mm left before board—panel cut‑out locked.” Fixing it now is an hour. After tiling, it’s a day and broken tiles.

Framing, Openings And Backing

The Problem

Wavy studs, off‑square openings and missing backing create finish problems that are hard to hide later.

The Solution

• Plumb, level, straight:
  • Sight every key wall. In general, aim for studs within a few millimetres of plane; many carpenters work to less than 3–5 mm deviation on visible runs.
  • Check door and window openings are true, square and sized for the frames. Note hinge side backing.
• Backing where loads will land:
  • Add noggins for wall‑hung items: basins, towel rails, cabinets, TVs, shower screens, grab rails. Mark centre heights and capture photos before insulation.
• Wet‑room and tile prep:
  • Ensure additional studs at shower enclosures and bath ends for screens and panels.
  • Confirm substrate choice for tiled areas (moisture‑resistant boards where specified).

Real‑World Example

A corridor feature wall will get battens and slats. You find two crowned studs pushing the plane by roughly 6 mm. You mark and note: “Plane studs at 2/4 to face flush; install 9 mm ply backing over run.” That prevents shadow lines telegraphing through a premium finish.

Air Sealing And Insulation Readiness

The Problem

Leaky penetrations and missing baffles cause draughts, cold spots and failed airtightness targets, which are harder to fix post‑board.

The Solution

• Penetrations and junctions:
  • Seal around pipes, wires, and boxes entering external walls and ceilings. Many contractors use foam or grommets and note “seal before insulation”.
  • Check top plate penetrations and service penetrations to loft are sealed.
• Downlights and boxes:
  • Confirm downlight type (fire‑rated/IC rated) and any required hoods. Seal to prevent air leakage where required.
• Attic/rafter spaces:
  • Fit insulation baffles at eaves to maintain ventilation. Mark any tricky junctions for the insulators.
• Part L mindset:
  • While exact targets vary by project, UK energy standards are tightening. Sealing penetrations now typically improves blower‑door results and reduces callbacks about cold draughts.

Real‑World Example

You spot four pipe penetrations along an external kitchen wall. You place blue tape at each and add a voice note: “Seal kitchen service penetrations before insulation; photo after.” Many contractors report that this simple step eliminates common “cold corner” complaints.

Document, Agree And Action The List

The Problem

Decisions made on site vanish by the time board goes up. That’s how you end up with arguments and unpaid extras.

The Solution

• Capture as you go:
  • Photograph every marked change with a tape measure or level in shot. Dictate the room, wall, measurement off a fixed reference, and what to do.
• Create a single action list the same day:
  • Turn your notes into a tidy, client‑friendly list: item, description, location, status, cost impact (if any), and who’s responsible.
  • For no‑charge clarifications, still list them. It sets expectations and protects finish dates.
• Get sign‑off before any rework:
  • Share a clear PDF the client can approve digitally. Many contractors find that electronic sign‑off reduces back‑and‑forth by half and keeps programmes on track.
• Track to done:
  • Re‑photo corrections before insulation and again before board, and mark each as complete.

Using Donizo To Make This Frictionless

• Talk and snap on site, then turn it into a clean document fast with Donizo:
  • Use Voice to Proposal to dictate each correction with photos; Donizo generates a professional, branded PDF list.
  • Send Proposal with client portal access so the client can review the action list the same day.
  • Use E‑signature Integration to get legally binding approval before rework.
  • If some items are chargeable, convert accepted items to invoices in one click with Invoice Management.

Real‑World Example

On a loft conversion, you identify 12 items (2 charged extras for additional backing, 10 zero‑cost clarifications). You dictate and photograph on site, send a branded PDF within an hour, and the client e‑signs that evening. The crew clears the list next morning. Commonly, this approach saves 2–3 hours of admin and prevents “we didn’t agree that” disputes.

Frequently Asked Questions

When Should I Schedule The Pre‑Drywall Walkthrough?

After first fix is complete, pressure tests passed, and before insulation or boarding. For a typical floor in a 3‑bed house, allow 45–60 minutes. Trying to do it after insulation often hides issues and increases rework.

What Tools Do I Need On The Day?

Plans, laser/tape, spirit level, step ladder, torch, markers/tape, and a phone for photos and voice notes. Bring a sample switch or back box if you’re checking depths. Blue/red tape is great for “fix” vs “confirm” marks.

How Do I Handle Disagreements On Positions?

Pause and show context: cabinetry lines, door swings, appliance clearances. Mark options A/B on studs, take photos, and agree one on the spot. Send a same‑day PDF summary for e‑signature so the choice is documented. Tools like Donizo help you capture and get sign‑off quickly.

Is A Walkthrough Worth It On Small Jobs?

Yes. Commonly, even on a single bathroom, a 20‑minute walkthrough catches tile backer placement, niche heights, valve centres and fan ducting. Fixing these after board or tile is 3–5 times the cost/time.

What UK Rules Should I Keep In Mind?

Use Approved Document M for accessible switch/socket heights guidance (sockets around 450 mm min AFFL; switches 900–1200 mm). Approved Document F for ventilation rates (bathroom 15 l/s intermittent; kitchen 30 l/s). Reference BS 7671 for cable safe zones and protection (cables less than 50 mm from surface require 30 mA RCD or mechanical protection).

Conclusion

A good pre‑drywall walkthrough is a quality gate: short, deliberate, and decisive. You’ll agree heights, routes and backing while changes are cheap, photograph evidence, and lock decisions with a signed action list. The payoff is fewer callbacks, cleaner finishes and a calmer handover.

Make it effortless: capture what you see and say on site, and turn it into an approval‑ready PDF with Donizo. Voice to Proposal, e‑signature and one‑click invoice conversion mean you can move from “spotted” to “approved” to “done” without typing marathons. That’s how small teams win their evenings back and still deliver like pros.