Showers & Bathrooms


Bathroom Flooring Tips - How To Lay A Sub-floor

Before you fit any type of bathroom flooring, it’s essential to make sure the sub-floor is prepared adequately to ensure it’s ready to take the flooring.  This is especially crucial in bathrooms, where the high moisture levels in the air can make any flooring more susceptible to damage.  How you should prepare your sub-floor depends on whether your bathroom floor is wooden or concrete.

Because it’s rigid, concrete makes a good base for flooring.  If you’ve got a new screed, it can take several months for the concrete to dry out completely before a new floor can be laid over it.  With old screed, you will need to make sure you’ve got a level surface, by either filling holes or applying a self-leveling compound.  Start by using a hammer and chisel to remove any lumps of concrete sticking up on the surface, as these could damage the new flooring.  Use either mortar or self-leveling compound to fill in any noticeable holes or dips.  Make sure there are no patches of bitumen left over from a previous floor covering, as this can stop the self-leveling compound settling properly.

Once you’ve done this, sweep off any loose dust and debris and apply a PVA solution, made up of 1 part PVA to 5 parts water.  Then, following the user instructions, mix up some self-leveling compound in a bucket to the desired consistency.  Pour this straightaway onto the screed and use a plastering trowel to spread it over the whole floor.  It should dry overnight to produce a level surface.  Once it’s dry, smooth off any rough spots with sandpaper. 

With a wooden floor, what condition it’s in will affect which type of floor covering would be best to use.  It also depends on what type of flooring you’re using as to how you prepare your sub-floor.  For example, if you’re laying vinyl or laminate flooring, a chipboard sub-floor should be sufficient.  But to lay tiles, you’ll have to lay a further sub-floor made from ply.  Bare floorboards will need the most work.

Before you start, make sure that all your floorboards are securely fixed in place if they’re not, screw them into position.  Using screws rather than nails means you can more easily gain access under the floor should you need to in the future.  Be careful not to screw through any pipes or cables.  A good way to level out uneven floorboards is to staple or nail 4ft x 2ft sheets of hardboard over the floor.

To cut hardboard to size, use a craft knife and a straight edge to score the surface, then snap it apart.  Use paper templates to cut the hardboard to fit around tricky bits, such as the base of a pedestal sink.  Cut out the required shape using a jigsaw, before slotting your hardboard into place.