Quick-Step Master Installer
Factory accredited installation
Free measure & quote
Fixed price, no obligation
Supply & install
One point of contact, start to finish
Bayside & South East
Local, family run, fully insured
Concrete Moisture Testing Before You Lay a Floor
The cheapest insurance in flooring. We test the slab properly, in writing, before a single box of product is ordered.
Google Rating
Based on 47 reviews
Most flooring failures start in the slab
Cupped timber. Lifted vinyl. Bubbling glue. Mould under an underlay. A hybrid floor that keeps clicking apart. Chase almost any flooring failure back far enough and you find the same thing. A slab that was still giving off moisture when the floor went down.
Concrete does not stop drying when it looks dry. A slab needs about one month of drying for every 25mm of thickness, in good conditions. So a standard 100mm slab poured in a Melbourne winter can still be too wet six months later. New builds are the most common problem. So are older slabs with no membrane underneath, ground floor extensions, and homes on a slope where ground water tracks under the house.
Every flooring maker sets a maximum moisture level for their product. Every one of them voids the warranty if the floor goes over a slab above that level. Testing is the only way to know. It costs a fraction of what a failed floor costs to replace.
Why it is worth doing before every installation
It takes a day or two and it protects tens of thousands of dollars worth of floor.
Protects the manufacturer warranty
Almost every flooring warranty requires documented moisture testing. Without it, a claim for cupping, lifting or adhesive failure is very likely to be declined.
Decides the installation method
A slab near the top of the range can still be fine for a floating floor with a vapour barrier. It can be wrong for direct stick. The test result tells us which.
Catches problems before you buy
Far better to know before the product is ordered and the installation booked than on the morning the crew arrives.
Documented in writing
You get the readings, the method used and the date. That is exactly what a builder, an insurer or a manufacturer will ask for.
Identifies rising damp early
High readings right across a slab often mean a missing or damaged vapour membrane. That is a building problem, and better to know now.
Cheap relative to the risk
Testing is a small line item. Pulling up and replacing a failed floor across a whole house is not.
How we test a slab
Australian Standard AS 1884 covers moisture testing for resilient floor coverings, and the makers all point to it. The method matters. A quick surface reading can show a slab as dry while the moisture is still sitting deeper in the concrete. Seal that surface with a floor and the moisture comes up.
Depending on the slab, the product and what the manufacturer requires, we use one or more of the following.
- In situ relative humidity probes, drilled into the slab at the right depth and left to settle. This is the most reliable method available
- Surface meter readings across a grid. We use these to map variation and find wet spots, not as a pass or fail result
- Plastic sheet and hygrometer testing where a simpler indicative check is appropriate
- Several test points. Slabs are rarely even, and the wet part is often near outside walls, wet areas, or where the slab meets fill
- Written results with readings, locations, method and date, ready to hand to a builder or lodge with a warranty claim
- Clear recommendations, whether that is wait, apply a moisture barrier system, change the installation method or proceed as planned
How a moisture test runs, step by step
Straightforward, non destructive and usually resolved within a couple of days.
1
Book the test
Tell us the slab age, the size of the area and the flooring you are thinking about. We will confirm which test method the maker requires.
2
Test points installed
We map the area, then drill probes to the right depth or set surface tests. They stay in place until the readings settle.
3
Readings and report
We return, take the readings and give you a written result with the method, locations and date recorded.
4
Recommendation
A clear next step: proceed, wait, or apply a moisture barrier system. If we are installing the floor, this feeds straight into the quote.
Slab preparation and testing
Where we work
Flooring installation across Bayside and South East Melbourne
Homeowners, builders and businesses, from the Brighton and Bentleigh renovations through to the Cranbourne estates and the Peninsula.
Bayside
Period homes, renovations and high end rentals close to the bay.
Brighton · Brighton East · Hampton · Hampton East · Sandringham · Black Rock · Beaumaris · Cheltenham · Highett · Mentone · Parkdale · Mordialloc · Bentleigh · Bentleigh East · McKinnon · Ormond · Elsternwick · Caulfield
Casey and Cardinia
New builds, house and land, and growing family homes.
Cranbourne · Cranbourne South · Cranbourne East · Botanic Ridge · Clyde · Clyde North · Berwick · Narre Warren · Officer · Pakenham · Beaconsfield · Hampton Park · Lynbrook · Lyndhurst · Endeavour Hills · Hallam
Greater Dandenong
Established homes, rentals and commercial fitouts.
Dandenong · Dandenong North · Keysborough · Noble Park · Springvale · Rowville · Lysterfield · Mulgrave · Wheelers Hill
Frankston and Peninsula
Coastal properties, holiday homes and investment stock.
Frankston · Frankston South · Langwarrin · Carrum Downs · Skye · Seaford · Mount Eliza · Mornington · Mount Martha · Somerville
Other flooring we supply and install
Frequently asked questions
Why does a concrete slab need moisture testing before flooring?
Concrete gives off moisture for months after it is poured. Lay a floor over a slab that is still too wet and that moisture gets trapped. It cups timber, lets go of vinyl glue, grows mould under underlay and lifts the joins in floating floors. Testing is the only way to know the slab is ready.
How long does a new concrete slab take to dry?
The rule of thumb is one month for every 25mm of slab thickness, in good drying conditions. So a typical 100mm slab needs around four months. Melbourne winters stretch that out. So do closed up buildings with no airflow, and slabs poured over wet ground. It is common for a slab to still be too wet at six months.
What moisture level is acceptable?
It depends on the product. Makers publish their own limits, usually as a maximum relative humidity inside the slab. We check the exact requirement for the floor you are looking at. We do not use a generic number, because the limits differ a lot between timber, vinyl and hybrid.
Is the testing destructive?
In situ relative humidity testing involves drilling small holes into the slab for the probes. They are small, they are patched afterwards, and they end up under the new floor. Surface and sheet testing are completely non destructive.
How long does the test take?
The probes need time to settle before they give a valid reading. That is usually 24 to 72 hours, depending on the method and what the maker requires. So it is one visit to install, then a second visit to read and report.
What if the slab is too wet?
You have three options. Wait and retest. Apply a surface moisture barrier rated to the reading. Or change the floor to something that copes better, like a floating floor over a vapour barrier. We will tell you which one actually applies to your slab, and what it costs.
Do you test slabs if someone else is installing the floor?
Yes. We test and write up the report for builders, owner builders and other trades. It makes no difference whether we are supplying the floor.
What our customers say
Rated 5.0 from 45 Google reviews across Bayside and South East Melbourne.
Book a concrete moisture test
Tell us the slab age, the area and the flooring you are thinking about. We will confirm the right test method and the price.
- Free, no obligation measure and quote
- Fixed price, so there are no surprises on the day
- Honest advice on which floor suits your rooms and your subfloor
- Old floor covering removal and disposal handled for you
Prefer to talk?
Phone 0422 635 797
Email admin@southsideflooring.com.au
