Tips on Matching Timber Flooring or Contrasting Concrete For Your Extension Flooring

Completing your extension is one thing, matching your home existing home is a whole other ball game. 

There’s really only 2 options to get it right: 

Jarrah floor variations or completely contrasting with polished concrete your extension flooring

Jarrah Flooring  

Jarrah is notoriously tricky when blending old with new, here is why  

Sourcing timber:

Try to source recycled jarrah boards from salvage yards Subi Restoration is a 

Good start or demolition suppliers. New jarrah is often denser, redder and cleaner-looking, so it will stand out against your existing, mellowed boards. 

Board size:

Match the width and thickness of your existing boards. Old jarrah was often cut in wider planks than modern tongue-and-groove. Get a carpenter/builder to customise it to suit your home.  

Colour variation: Expect a difference. Even recycled boards won’t perfectly match what’s been ageing in your home for 30+ years.  

Worst thing you can do is try and match them and get it wrong. It will stick out like no tomorrow.  

You could – Laying the new section with a border strip or threshold so it looks intentional rather than a bad colour match. 

Use stains or tinted polyurethane after sanding the whole area together to even out tones. Although if your boards have been sanded back too many times, you may not be able to do it again.  

You do a different pattern (Herringbone) for example. Running new boards in a slightly different direction if the space allows (kitchens often do this).

Sanding:

If you sand only the new area, it will still look different. Ideally, sand back all the existing jarrah at the same time and finish in one go. This is the best way to disguise old/new differences. 

Polished Concrete Finish in the New Area

Polished concrete is a completely different beast to timber. It looks awesome with modern extensions to old homes. Very popular in Kenso but trickier.  

Key Tips: 

Slab quality matters:

Concrete polishing doesn’t “cover up” flaws. The slab needs to be laid flat, with a good finish, no messy trowel marks, and proper curing. Tell your concreter you plan to polish it—otherwise you’ll inherit their shortcuts. 

Aggregate exposure:

Decide upfront if you want a “cream finish” (smooth, minimal stone showing), “salt and pepper” (light stone exposure), or “full stone” (lots of aggregate). This determines how much grinding is done. 

Colour & cracks:

Expect some natural cracking and colour variation, which I think is part of the charm. If you want consistent colour, ask for integral colour oxide mixed through the pour. 

Finish & slip resistance:

High-gloss isn’t my style but can look amazing, although can be slippery. A satin or matte finish is often more practical for kitchens and living areas. 

Maintenance:

Sealing is essential. You’ll need a penetrating sealer to resist stains from red wine, oils, etc. Unlike tiles, you can’t just replace one slab if it’s damaged. 

Thermal considerations:

Concrete floors hold cold in winter. Use rugs in living areas to soften the feel. 

lf you want seamless flow between jarrah and concrete, consider a transition strip (brass, timber, or recessed shadow line) so it looks deliberate. If you want contrast, let the two materials speak for themselves, jarrah warm, concrete cool. 

That’s a little more than you asked for but I hope it helps.