Open Plan Kitchen Living Room: Converting and Plastering

Understanding Open Plan Kitchen Living Spaces

Open plan kitchen living rooms have become the gold standard for modern UK homes. By removing the wall between your kitchen and living room, you create a bright, sociable space that’s perfect for family life and entertaining.

The conversion isn’t just about knocking through a wall, though. You’ll need to consider structural implications, Building Regulations compliance, and—crucially for a perfect finish—extensive plastering work to make the newly opened space look like it was always meant to be one room.

We’ve completed dozens of these conversions across Kent, and the plastering stage is where many DIY projects fall short. Let’s walk through exactly what’s involved, from the initial structural assessment right through to that final skim coat.

Planning Your Open Plan Conversion: What You Need to Know

Structural Considerations

The first and most critical question: is the wall you want to remove load-bearing? This determines everything else about your project.

Load-bearing walls support the structure above—floor joists, upper floors, or roof weight. Removing one requires installing a steel beam (RSJ) or engineered timber beam to transfer the load. Non-load bearing (partition) walls simply divide space and can be removed more easily.

• External walls: Almost always load-bearing
• Walls running perpendicular to floor joists: Usually load-bearing
• Walls at the centre of the house: Often load-bearing
• Stud partition walls: Rarely load-bearing (but check anyway)

Building Regulations Approval

You’ll need Building Regulations approval for knocking through walls, even if planning permission isn’t required. This applies to both load-bearing and non-load bearing walls according to UK Building Regulations.

Your local authority building control will inspect at key stages: before you start, when the beam is installed, and when the work is complete. Factor in £300–£500 for building control fees and 2-4 weeks for approval.

The Knock Through Process: Step-by-Step

Stage 1: Preparation and Temporary Support

Before any wall comes down, you need temporary supports (Acrow props) to hold up the structure above. These adjustable steel columns are positioned either side of where the beam will go.

For a typical 4-metre opening, you’ll need 4-6 Acrow props with scaffold boards (strongboys) to distribute the load. This isn’t optional—the ceiling will crack or collapse without proper support.

Stage 2: Installing the Beam

If you’re dealing with a load-bearing wall, a structural engineer will specify the beam size based on the span and load. Common options for domestic projects:

Steel beams (RSJs) are most common because they’re strong, reliable, and building inspectors understand them well. The beam sits on padstones—concrete or steel plates that spread the load onto the masonry either side.

Stage 3: Removing the Wall

With the beam in place and approved by building control, the old wall can be carefully removed. This creates enormous amounts of dust and debris—expect at least 10-15 heavy-duty rubble bags from a single wall.

Professional builders use cutting equipment to minimise vibration damage to surrounding plaster. Sledgehammers work but often crack plaster in adjoining rooms, creating more remedial work.

The Plastering Challenge: Making It Look Seamless

Here’s where most DIY conversions fall apart. The structural work might be sound, but poor plastering screams “renovation” rather than achieving that seamless open plan look.

What Needs Plastering After a Knock-Through?

Removing a wall affects five surfaces that need attention:

• The beam soffit: Underneath the new RSJ or timber beam
• Both reveals: The sides where the old wall met the remaining walls
• Ceiling patches: Where the wall intersected the ceiling
• Floor level: The gap left by removing the wall base
• Any damaged areas: Cracks or loose plaster caused by vibration

Boarding Out the Beam

Steel beams must be boxed in with plasterboard before plastering—both for aesthetics and fire protection under Part B of the Building Regulations.

We typically use 12.5mm standard plasterboard or 15mm fire-resistant board depending on the structural engineer’s specification. The framework is built from 50×25mm timber battens screwed to the beam and walls.

The plasterboard joints are then taped with scrim or paper joint tape and filled with Gyproc EasiFill or similar joint compound. This creates a level base for the skim coat. For more detailed information on boarding techniques, see our guide on how to plasterboard a room.

Making Good the Reveals

Where the old wall met the existing walls, you’ll have an exposed edge—sometimes just plasterboard, sometimes a mix of brick, block, and old plaster. These reveals need careful preparation:

1. Remove any loose plaster back to sound material (tap the wall—loose areas sound hollow)
2. Cut back to create a clean edge using a bolster chisel and hammer
3. Apply PVA bonding agent diluted 1:3 with water (two coats, letting first coat go tacky)
4. Build up level with the existing wall using bonding plaster or Hardwall
5. Once set (2-3 hours), apply final skim coat using British Gypsum Multi-Finish

The key is feathering out the new plaster so it blends seamlessly with the old. This takes experience—you’re typically working across a 300-500mm width, gradually thinning the new plaster from 15mm thick right down to paper-thin at the edge.

Ceiling Repairs

The ceiling is often the trickiest part. Where the wall met the ceiling, you’ll have either a gap to fill or damaged existing plaster to repair.

For gaps up to 50mm wide, we cut back to the nearest joists, then fit plasterboard tight to the existing ceiling. The joint is then filled and taped before skim coating across the entire ceiling for a uniform finish.

Trying to plaster just a strip across the ceiling looks dreadful—the difference in texture and colour is obvious. Budget for skimming the entire ceiling if you want professional results. Check our ceiling plastering costs guide for current pricing.

Floor Level Considerations

Removing a wall leaves a channel where the wall plate (sole plate) was. This needs filling to match your floor level.

For concrete floors, use a rapid-setting floor levelling compound like Mapei Ultraplan Renovation. For timber floors, fit a matching timber infill piece between the joists, then overlay with ply or whatever your finished floor will be.

Plastering Materials and Tools for Open Plan Conversions

Essential Materials

All these materials are readily available from Travis Perkins, Screwfix, or Wickes. We prefer British Gypsum products for consistency—their Multi-Finish has a reliable 90-minute working time, which matters when you’re plastering large areas.

Specialist Tools You’ll Need

Standard plastering tools apply, but open plan conversions benefit from a few extras:

• 14-inch plastering trowel: For large, flat areas (the beam soffit)
• 6-inch gauging trowel: For tight spaces and reveals
• Darby (feather edge): 1200-1500mm long for levelling beam soffits
• Internal corner trowel: Essential for tight reveals
• Paddle mixer and heavy-duty drill: For consistent mixing (see our mixing drill guide)
• Plasterer’s stilts: Makes ceiling work far less exhausting

Cost Breakdown: What to Budget for Your Open Plan Conversion

Costs vary significantly depending on whether the wall is load-bearing, span width, and your location in Kent. Here’s what we typically quote in 2026:

Structural Work

Plastering Work

Total plastering costs typically range from £1,100 to £1,800 for a standard knock-through. This assumes the plasterer is working on prepared surfaces and doesn’t include decorating.

Timeline: How Long Does an Open Plan Conversion Take?

Here’s a realistic timeline from our recent projects:

• Structural engineer visit and calculations: 1-2 weeks
• Building Regulations submission and approval: 2-4 weeks
• Ordering beam and materials: 1-2 weeks
• Physical knock-through and beam installation: 2-3 days
• Building control inspection: 1-5 days (book in advance)
• Plasterboard boxing and first fix: 1 day
• Drying time: 24 hours
• Plastering reveals, beam soffit, and ceiling: 2-3 days
• Plaster drying time: 7-14 days (depending on weather and ventilation)
• Mist coat and decoration: 2-3 days

From start to finish, expect 6-10 weeks for the entire project including regulatory approval. The actual on-site work is typically 7-10 days, but drying times and inspections extend the overall timeline.

Common Problems and How to Avoid Them

Cracking Along the Beam Line

This is the number one complaint after open plan conversions. Cracks appear along the beam soffit or where new plaster meets old.

Causes:

• Insufficient screws in the plasterboard (should be every 150-200mm)
• No scrim tape over joints
• Applying skim coat before jointing compound has fully dried
• Natural settlement of the new beam (slight movement is normal)

Prevention: Use quality jointing compound, tape all joints properly, and consider leaving the beam boxing for 3-4 weeks before skimming if you’re concerned about settlement. Some movement is inevitable, but proper preparation minimises visible cracking.

Visible Height Differences

The new plastered beam soffit should align perfectly with the existing ceiling height, but inexperienced plasterers often get this wrong.

Prevention: Set accurate datum points using a laser level before starting. The plasterboard should sit 13-15mm below the finished ceiling level to allow for the skim coat thickness. Mark this clearly on both ends before fixing any boards.

Colour Variation Between New and Old Plaster

New plaster is bright white; old plaster yellows over time. This difference can be stark, even after painting.

Solution: Apply a mist coat of diluted matt emulsion (5 parts paint to 1 part water) to the entire wall and ceiling area, not just the new plaster. This creates a uniform base. Then apply two coats of your chosen finish colour. Learn more in our guide on preparing new plaster for painting.

Damp Issues After Opening Up

Removing walls can sometimes expose previous damp problems that were hidden behind the old partition. You might find damp patches on the external wall that was previously concealed.

Action required: Never plaster over damp areas. Investigate the source (rising damp, penetrating damp, condensation) and resolve it first. For more information, read our article on damp patches on plastered walls.

Lighting, Heating and Electrical Considerations

Opening up two rooms creates new practical challenges that affect your plastering schedule:

Recessed Lighting in Beam Boxing

Many homeowners want downlights fitted into the beam soffit. This needs planning before the plasterboard goes up.

Your electrician should mark out light positions and drill the plasterboard before installation. We typically use fire-rated LED downlights (50-60mm diameter) spaced 800-1000mm apart along the beam length.

Coordinate trades: Have the electrician run cables and fit lights before plastering starts. We then skim around the fitted lights—it’s easier than cutting neat holes afterwards.

Radiator Repositioning

Removing a wall often means moving radiators. The new pipework may need chasing into walls or running under the floor.

If pipes are surface-mounted on the walls you’re plastering, this adds complexity. We prefer to have heating engineers complete all pipework before plastering, then plaster right up to the pipes and brackets.

Achieving That “Always Been There” Finish

The hallmark of professional work is that you can’t tell where new meets old. Here’s how we achieve that:

• Feathering technique: New plaster is gradually thinned over 400-600mm so there’s no visible edge
• Matching ceiling texture: If existing ceilings have a stippled or textured finish, we replicate it on new sections
• Consistent skim thickness: Varies by area, but ceiling skim is typically 2-3mm, wall skim 2-4mm
• Proper curing: Windows closed but dehumidifier running for first 24 hours, then ventilation to complete drying
• Full-room decoration: Never just paint the new plaster—paint the entire space for colour consistency

DIY vs Professional: When to Call in the Experts

The structural work—removing walls and installing beams—should always be done by qualified builders or structural engineers. The risks are simply too high.

The plastering? That depends on your skill level:

Consider DIY Plastering If:

• You’ve successfully plastered walls before
• The project is relatively simple (non-load bearing wall, small span)
• You’re not concerned about perfect results
• You have time to learn and make mistakes

Hire Professionals If:

• This is your first plastering project
• You want a seamless, invisible finish
• You’re dealing with large ceiling areas
• The timeline is critical (professional plasterers work much faster)
• You’re mixing with period features that require sympathetic restoration

In Kent, expect to pay £180-£250 per day for a qualified plasterer, or £900-£1,800 for a complete open plan conversion plastering package. It’s worth getting multiple quotes and checking recent work. Read our guide on finding a reliable plasterer in Kent.

Design Ideas for Your New Open Plan Space

Once the plastering is complete, you have a blank canvas. Here are popular design approaches we’ve seen work well:

Defining Zones Without Walls

• Different flooring materials: Tiles in kitchen area, engineered wood in living space
• Ceiling treatment: Lower the ceiling slightly over the kitchen using a suspended ceiling or bulkhead
• Partial walls/posts: Keep short sections of wall (900-1200mm high) to create subtle division
• Furniture placement: Sofa facing away from kitchen creates psychological boundary
• Lighting zones: Separate circuits for kitchen task lighting vs living area ambient lighting

Exposing vs Boxing the Beam

You have two aesthetic choices for the structural beam:

Box it in (most common): Creates a clean, contemporary look. The plastered beam soffit becomes part of the ceiling plane and virtually disappears when painted.

Expose it (industrial style): Leave the steel beam visible and paint it black or grey. This works brilliantly in industrial or modern farmhouse designs. If choosing this option, discuss with your structural engineer—some beams need fire protection boarding even if you want an “exposed” look. The boarding can be painted to match the steel.

Frequently Asked Questions

Can I remove a wall between my kitchen and living room without planning permission?

Yes, you typically don’t need planning permission for internal alterations. However, you do need Building Regulations approval before starting work. This applies whether the wall is load-bearing or not. Your local building control will want to inspect the work at various stages. Starting without approval can cause serious problems if you later sell the property—buyers’ solicitors will request building control certificates, and retrospective approval is difficult and expensive.

How long does the plaster need to dry before I can paint?

Modern gypsum plasters (Multi-Finish, Board Finish) are touch-dry in 2-3 hours, but require 7-14 days to fully cure before painting. The exact time depends on temperature, humidity, and ventilation. In winter or damp conditions, allow the full two weeks. The plaster should be uniform pale pink colour (for Multi-Finish) or light grey (for Board Finish) when ready. Dark patches indicate trapped moisture. Apply a mist coat first (5:1 paint to water ratio) before full-strength coats.

Will removing a wall create cracks in other rooms?

Some hairline cracking is common, especially in older properties. The vibration from demolition can disturb plaster in adjacent rooms, and the structural adjustment from installing a beam sometimes causes minor movement. Professional builders minimise this by using cutting tools rather than sledgehammers and properly supporting the structure during work. Small cracks are easily repaired with decorator’s caulk or filler. Major cracking suggests inadequate temporary support during installation—consult a structural engineer immediately if you see large cracks appearing.

What’s the best plaster to use for an open plan conversion?

For the skim coat on plasterboard and prepared surfaces, use British Gypsum Multi-Finish or Thistle Board Finish. Multi-Finish is more forgiving with a 90-minute working time, making it ideal for larger areas or less experienced plasterers. For building up deeper sections (like reveals), use Thistle Bonding Coat or Hardwall first, then skim with Multi-Finish once it’s set. Never use bonding plaster as a finish coat—it’s too coarse and doesn’t achieve the smooth surface needed.

Should I skim the entire ceiling or just the damaged sections?

Always skim the entire ceiling for a professional finish. Patching just the damaged sections leaves visible texture differences, colour variation, and join lines that are obvious even after painting. The marginal cost difference between patching and full skimming is minor compared to the aesthetic benefit. A full skim costs around £300-500 for a typical 4×4 metre ceiling, while patching might save you £100-150 but looks noticeably inferior. For larger rooms, the proportional cost difference is even smaller.

Do I need to move out during the work?

Not usually, but expect significant disruption. The structural work creates massive amounts of dust despite dust barriers. Most families decamp to other rooms or relatives’ homes for the 2-3 days of heavy demolition work. Once the wall is removed and beam installed, the plastering stage is much cleaner. You can usually stay in the house during plastering, though you won’t be able to use the affected rooms. Keep children and pets away from the work area—wet plaster is a magnet for curious fingers and paws.

Final Thoughts: Planning Your Open Plan Conversion

Converting to an open plan kitchen living room transforms how you use your home. Done properly, it adds genuine value—estate agents consistently report that open plan layouts command a 5-10% premium over equivalent closed-plan properties in the current UK market.

The key to success is proper planning and professional execution of the structural and plastering work. Cut corners on the structural engineering and you risk your home’s safety. Rush the plastering and you’ll live with visible joins, cracks and damp patches for years.

At Kent Plasterers, we’ve completed dozens of open plan conversions across Kent, from Maidstone to Canterbury, Tunbridge Wells to Dartford. We work closely with trusted structural engineers and building control to ensure every project meets UK regulations while achieving that seamless finish that makes the conversion look original.

Get your structural assessment done early, factor in realistic budgets and timelines, and don’t compromise on the quality of your plasterer. The difference between adequate and excellent plastering work is the difference between a conversion that shouts “renovation” and one that looks like it was always meant to be.