Kitchen Diner Knock Through

Kitchen Diner Knock Through – Real Project Case Study, Costs & Design Tips

Open-plan kitchen diners are one of the most requested home improvements in the UK. They combine practicality with style, giving homeowners a space that’s perfect for family life, entertaining friends, and letting natural light flood the home.

At CG Building Services, we’ve completed dozens of these projects — and in this article, we’ll take you through one of our recent kitchen diner knock through transformations. We’ll share the exact steps we took, the challenges we faced, the cost breakdown, and plenty of design tips so you can see how to achieve similar results in your own home.

The Client Brief

Our clients, a young family living in a 1930s semi-detached property, wanted to remove the internal wall between their small galley kitchen and the separate dining room. The goal was to create a single, bright, open-plan room where they could cook, eat, and spend time together without feeling cut off.

They also wanted space for a breakfast bar, better access to their rear garden, and a layout that allowed them to keep an eye on their children while cooking.

Initial Survey and Planning

Before we start any kitchen diner knock through, we carry out a detailed site survey. This involves:

1. Checking if the wall is load-bearing – in this case, it was. The wall supported the upstairs floor joists and part of the roof structure.
2. Measuring the opening size – the clients wanted the full width of the two rooms opened up, which was just over 4 metres.
3. Assessing plumbing and electrics – there were radiator pipes and a couple of sockets on the wall, which would need moving.
4. Discussing layout ideas – we talked through different kitchen arrangements, lighting positions, and flooring options.

We also liaised with a structural engineer to get calculations for the steel beam required.

Dealing With Building Regulations

For any structural kitchen diner knock through, building regulations approval is a must. We handled all the paperwork and coordinated with the building inspector.

The main points covered were:

• The correct size and load rating for the RSJ (rolled steel joist)
• Fire safety requirements
• Proper bearing on padstones
• Adequate support during installation

The inspector visited twice — once before the beam was installed, and again after completion to sign the work off.

The Construction Process

Step 1 – Setting Up

We protected floors with dust sheets, sealed off other rooms to minimise dust, and set up temporary supports (Acrow props and strongboys) to hold the structure before the wall was removed.

Step 2 – Wall Removal

We carefully removed the plaster to expose the brickwork, then took the wall down in sections. Because it was a load-bearing wall, this was done slowly and safely to avoid any damage to the structure above.

Step 3 – Installing the RSJ

The RSJ was lifted into place with a genie lift and bedded on concrete padstones at each end. We double-checked the level before bolting everything securely.

Step 4 – Making Good

Once the structural work was complete, we boxed in the beam with fire-rated plasterboard, plastered the entire ceiling for a seamless look, and patched the walls ready for painting.

Step 5 – Electrics and Heating

We moved the radiator to a side wall and rewired sockets to suit the new kitchen layout. We also added LED downlights and pendant lighting over the breakfast bar.

Step 6 – Flooring

The clients chose a luxury vinyl tile (LVT) in a herringbone pattern, running through the whole space to visually tie the two areas together.

Project Challenges

Even with a straightforward plan, a kitchen diner knock through can throw up unexpected issues:

• Hidden pipework – we found an old lead water pipe inside the wall, which we replaced with modern copper piping.
• Uneven floors – the kitchen and dining room floors were at slightly different heights, so we levelled them before laying the new floor.
• Lighting circuit upgrade – the existing wiring wasn’t up to modern standards, so we updated it for safety.

Addressing these issues added about 2 days to the project, but it ensured the clients had a safe and long-lasting finish.

Timescale & Cost

This kitchen diner knock through took 10 working days from start to finish.

Cost breakdown:

Design Tips for Your Own Project

If you’re thinking about a kitchen diner knock through, here are some tips we recommend to all our clients:

Plan Your Layout Early

Decide on your kitchen units, appliances, and dining area positions before work starts. This prevents last-minute changes that can delay the project.

Lighting is Key

Mix overhead downlights with pendant lighting and under-cabinet strips. This keeps the space bright but adaptable for different uses.

Think About Storage

Open-plan spaces can quickly feel cluttered — include plenty of built-in cupboards or shelving.

Match Flooring Across the Space

Using one flooring type makes the room feel bigger and more cohesive.

Factor in Noise

Open layouts can be noisier. Soft furnishings, rugs, and curtains help absorb sound.

Before and After

Before:

• Two separate, small rooms with poor light flow.
• The kitchen felt cramped and isolated from the dining room.
• Dark colours and dated finishes.

After:

• One bright, open space that connects the kitchen, dining, and garden.
• A stylish breakfast bar creating a natural divide between cooking and eating areas.
• Modern, low-maintenance finishes that suit a busy family.

Client Feedback

The clients were delighted with their new space:

“We can’t believe the difference. It feels like we’ve doubled the size of our downstairs without moving house. The team were brilliant from start to finish — tidy, professional, and kept us informed all the way through.”

Final Thoughts

A kitchen diner knock through is one of the most effective ways to modernise your home. It brings more light, improves flow, and creates a social hub for the whole family.

If you’re ready to explore your own project, CG Building Services can handle everything — from initial survey to final sign-off — with the attention to detail and craftsmanship we’re known for.