How Long Does a Wall Knock-Through Take? (Plan with Confidence)

The Fast-Track Formula: What Affects Your Wall Knock-Through Timeline?

The Three Biggest Time Factors: Load-Bearing vs. Non-Load-Bearing Walls

A wall knock-through isn’t just about swinging a sledgehammer and hoping for the best. The type of wall you’re dealing with is the first major factor that dictates how long the job will take.

If it’s a non-load-bearing wall, you’re in luck. These walls don’t hold up any structural weight, so once you’ve checked for hidden pipes and wires, it’s usually a straightforward demolition job. A skilled team can knock it down in one to two days.

But if it’s a load-bearing wall, things get a bit more complicated. This type of wall supports the structure above, meaning you’ll need proper reinforcement—usually an RSJ (Rolled Steel Joist) beam. Before the demolition even starts, you’ll need a structural engineer’s assessment and possibly building regulations approval.

Once the paperwork is in place, the actual work takes longer. Temporary supports must be installed to hold up the structure while the new beam is put in place. Depending on the wall’s size and the project’s complexity, this can add several days to a week to your timeline.

And here’s something most people don’t consider—if your house is older, expect extra delays. Many period homes have walls that aren’t uniform, making the installation of support beams trickier. Sometimes, original brickwork needs reinforcing before you can even install the RSJ.

Hidden Surprises: How Plumbing, Electrics, and Structural Issues Can Slow You Down

No two knock-throughs are the same. Even if your neighbour had a smooth experience, yours might hit unexpected snags. The most common culprits? Plumbing, electrics, and structural surprises.

If the wall you’re removing contains water pipes, gas lines, or electrical wiring, things get more complicated. These need to be rerouted safely before demolition begins. A plumber or electrician will need to assess the situation, shut off utilities, and carry out the work. This can add anywhere from a couple of days to over a week depending on the complexity.

Then there’s the wildcard—hidden structural issues. Old timber beams, crumbling brickwork, or inadequate foundations can all throw a wrench into your timeline. If your builder finds unexpected weaknesses in the surrounding walls or ceiling, they’ll need to reinforce them before proceeding. In extreme cases, this can add weeks to the project.

One way to avoid nasty surprises? Get a thorough pre-project survey. A structural engineer can identify potential risks before work begins, saving you time and stress down the line.

DIY vs. Hiring Professionals: How Your Choice Impacts the Project Duration

Thinking of knocking through a wall yourself? It’s tempting—after all, how hard can it be? But here’s the truth: unless you have professional experience, a DIY wall knock-through can take significantly longer and cost you more in the long run.

If you go the DIY route, you’ll need to:

• Get a structural engineer’s report (which can take a week or more).
• Apply for any necessary building regulations approval.
• Rent specialist tools for safe demolition.
• Source and install the correct support beam.
• Hire a plasterer, electrician, and plumber to finish the job.

Even if you’re experienced, this can take several weeks to a month, especially if you’re doing it around your day job. One mistake—like misjudging the weight load of a wall—can lead to costly structural damage.

On the other hand, hiring professionals streamlines the process. A good builder with experience in wall knock-throughs can complete the job in five to ten days, depending on complexity. They’ll handle the demolition, structural support, and initial finishing work like plastering. Plus, they’ll likely have electricians and plumbers on hand to deal with any last-minute surprises.

The key to keeping things on schedule? Hire a team with proven experience in structural work. A general builder may take longer if they’re unfamiliar with RSJs or dealing with complex load-bearing walls. Always check reviews and ask for case studies before hiring.

Step-by-Step Breakdown: How Long Each Stage of a Wall Knock-Through Takes

Pre-Project Prep: Surveys, Planning Permission, and Structural Calculations

You can’t just grab a sledgehammer and start swinging. Before the first brick comes down, there’s a crucial prep phase. This stage sets the foundation—literally—for a smooth wall knock-through.

First, you need to determine if the wall is load-bearing. If it is, you’ll likely need a structural engineer to assess it. This process alone can take one to two weeks, depending on availability.

Next up: building regulations approval. In the UK, knocking through a load-bearing wall requires compliance with Building Regulations Part A. If you’re making major alterations, you might also need approval under Part B (fire safety) and Part L (energy efficiency). You’ll either submit a Building Notice (fastest option) or apply for Full Plans Approval, which can take up to 8 weeks.

If your home is listed or in a conservation area, planning permission might be a factor. This can add another 8 to 12 weeks to the timeline. Most wall knock-throughs don’t need planning permission, but it’s better to check with your local authority than face delays later.

Structural calculations are next. If you need an RSJ beam or additional support, an engineer will provide precise load calculations. This usually takes one to two weeks.

Finally, you’ll need to hire the right professionals. Getting quotes from builders, checking references, and finalising a contract can take another two weeks, depending on how quickly you move.

Total time for pre-project prep: 2 to 12 weeks (varies based on structural complexity and approvals).

Demolition to Structural Support: How Long the Core Work Actually Takes

Once the paperwork is sorted, it’s time for the real action. The demolition phase is fast—but messy. If the wall is non-load-bearing, expect one to two days of work. A load-bearing wall? That’s a whole different game.

For a load-bearing wall, the first step is temporary support. Acrow props and strongboys hold up the ceiling while your contractor removes the wall. This can take one to two days, depending on the size of the opening.

Next, the RSJ beam installation. Once the old wall is gone, the steel beam (or lintel) is fitted into place. This involves precise positioning, securing it with padstones, and ensuring everything is structurally sound. This usually takes two to three days.

If plumbing or electrics run through the wall, expect additional delays. Rerouting pipes or rewiring can add another two to five days, depending on complexity.

After the beam is in place, it’s time to make everything solid again. Brickwork repairs, plasterboarding, and securing the new opening take three to five days. If you’re extending the flooring or ceiling to match the new space, add another two to three days.

Total time for demolition and structural support: 5 to 12 days (longer if plumbing/electrics need rerouting).

Finishing Touches: Plastering, Painting, and Making It Move-In Ready

At this stage, the hardest work is done, but you’re not finished yet. The final stretch is all about making the space look polished.

First, plastering. Fresh plaster needs time to dry before painting, and that’s where many homeowners get impatient. Standard plastering takes one to two days, but drying time adds another 5 to 7 days. If you’re using modern quick-dry plaster, you might shave a couple of days off, but patience here prevents cracks later.

Once dry, painting and decorating begin. This depends on the size of the space and the level of detail. A simple repaint takes two to three days, but if you’re installing new skirting boards, doorframes, or feature walls, expect another three to five days.

Flooring is next. If you need to extend existing flooring or lay new materials, allow two to four days for installation and finishing.

Finally, the deep clean. Wall knock-throughs generate a shocking amount of dust, even with protective measures. A thorough clean-up takes one to two days, especially if dust has spread to other rooms.

Total time for finishing touches: 10 to 14 days.

If you want to speed up the process, planning ahead is key. Hiring professionals who stick to deadlines can make all the difference. For more expert advice on making your wall knock-through safe and simple, check out this guide.

Speed Hacks: How to Avoid Delays and Keep Your Wall Knock-Through on Track

Essential Pre-Planning: The One Thing That Can Save You Days (or Even Weeks)

Before the first hammer swings, your number one priority is planning. A well-planned wall knock-through moves fast. A poorly planned one? Expect chaos, delays, and unexpected costs.

The biggest time-saver is getting your structural engineer report early. This tells you whether the wall is load-bearing, what type of support you need, and if additional reinforcements are required. Without it, you’re flying blind. Worse, your builder may stop mid-project, waiting for calculations.

If your wall is structural, you may need building regulations approval. This isn’t optional—it’s the law. Applying early avoids last-minute holdups. In most UK councils, approval takes 5-8 weeks. If you need a Party Wall Agreement (because your wall is shared with a neighbour), factor in extra time. Some agreements take months if neighbours dispute the work.

Book your tradespeople in advance. Good builders get booked up fast. If you wait until demolition day to find a plasterer or electrician, you’ll be stuck with long gaps between stages. Align all your trades before the work begins.

Materials matter too. Order your steel beam (if needed) well ahead of time. Some RSJs take weeks to arrive, and a missing beam halts everything. Same goes for skips, plasterboard, and finishing materials. If they’re not on-site when needed, expect delays.

Want a pro tip? Set up a WhatsApp group with your builder, engineer, and key trades. Quick communication solves problems before they spiral.

Hiring the Right Team: How to Choose Professionals Who Stick to Deadlines

Not all builders work at the same pace. Some finish ahead of schedule. Others drag a simple job out for weeks. Choosing the right team is everything.

Start with recommendations. Ask friends, family, or local Facebook groups for builders who are reliable and efficient. Check reviews, but also ask past clients how well they stuck to the timeline.

When interviewing builders, ask:

• How many similar wall knock-throughs have you done?
• Can you provide references for recent jobs?
• What’s your estimated timeline for completion?
• How do you handle unexpected delays (weather, material shortages, etc.)?

Avoid anyone who’s vague about timing. A good builder gives you a clear start and end date. Even better, they put it in writing.

Ask about their subcontractors. Many builders bring in separate electricians, plasterers, or plumbers. If these tradespeople aren’t lined up properly, you’ll have dead time between stages. Ensure your builder has a solid team that can slot in seamlessly.

Payment structure also affects speed. Never pay the full amount upfront, but staged payments tied to progress keep things moving. A builder working towards milestones is more motivated to stay on track.

One red flag? Builders who say they can “squeeze you in” between jobs. This often means they’ll leave mid-project to work elsewhere, causing delays. Book professionals who commit fully to your job.

Minimising Disruption: Smart Scheduling Tricks to Get It Done Faster

Renovations are messy. The more efficiently you schedule your wall knock-through, the less disruption you’ll face.

Plan your knock-through when it suits your lifestyle. If you work from home, the noise and dust might be unbearable. Consider scheduling work when you’re on holiday or staying elsewhere. If that’s not possible, set up a dust-free zone in another part of your home.

Minimise downtime between stages. If demolition finishes on Friday but the beam isn’t installed until Tuesday, that’s wasted time. Ensure there’s a seamless transition from one phase to the next.

Think about the knock-on effects. Moving electrics or plumbing? Get your electrician and plumber in the loop early. If they’re not available when needed, you’ll be stuck waiting.

Tidy job sites move faster. Builders waste time navigating clutter. A clear workspace speeds things up. Ask your team to clean up daily, removing rubble and keeping tools organised.

Want to cut disruption further? Invest in temporary dust barriers. Zip doors, plastic sheeting, and air purifiers keep dust from spreading, making the clean-up quicker.

Time is money in renovations. Smart planning, the right team, and tight scheduling keep your wall knock-through on track. To avoid delays and get expert guidance, check out our Structural Engineer Reports here.