Adhesives – How to install a floor using adhesive
Both solid and engineered floors can be installed using adhesive. There are two main techniques for installing using adhesive which will both be explained. Please remember that solid floors are always recommended to be glued down, not using the floating method.
Floating Floor Method
The floating floor method of fixing the floor is done by gluing the tongues and grooves of the floor together. This creates a new floor which is “floating” over the original floor.
Floors can be floated over any solid subfloor and it is the preferred method for laying engineered floors.
It is a good option when the subfloor moisture content is unknown as a damp proof membrane can be used between the floor and subfloor to prevent moisture rising into the new flooring.
When floating a floor, an underlay must be used to dampen any echo and extra noise. This echo is caused by two hard surfaces together which have a space between them. The noise echoes in this void. The underlay is used to prevent any echo as the two hard surfaces will not be touching.
There is a wide range of underlays for use when floating the floor – all of which are adequate. The more dense the underlay is the less sound echo there will be from foot traffic.
To float the floor:
Lay out the damp proof membrane (if required) ensuring that the edges of the membrane continue up the side of the skirting.
Lay out the underlay ensuring all areas of the floor are covered. Any areas left uncovered with the underlay will cause a bounce in the new floor and will be noisier.
A PVA adhesive is used to glue the boards together.
Fit the floor by placing two beads of adhesive along the upper and lower sides of the “groove” joint. (It is a common mistake to think that the boards need to be glued along the “tongue” – this will simply push the adhesive too far into the joint and not create a firm bond between the boards.) You must ensure that the beads of glue are constant and not intermittent as this can cause the boards to creak if the joint is not constant.
Leave the joints and glue to dry before walking on the floor. Any PVA glue which has spilled onto the boards can easily be wiped off a lacquered or oiled board, or sanded off an unfinished floor.
It must be noted that thermo treated solid oak has less density therefore water based pva will not adhere to the timber as well as normal oak. When using solid thermo treated oak it is best to use another fitting option, however if the boards are engineered this is not a problem as the tongue and grooves are made from the softwood base.
Glue Down Method
The glue down method of fitting a floor consists of using a strong, thick floor specific adhesive applied directly to the subfloor enabling the new floor to stick directly to the original floor. This is a very sturdy method which is the recommended option for solid boards and parquet floors. To fit a floor using the glue down method you must ensure that the subfloor is dry, level and structurally sound. When fitting onto concrete it is best to prime the area first using a PVA based primer to ensure a good bond to the floor. Any old concrete is recommended to be checked for moisture before the boards are laid.
Both engineered and solid boards can be laid using the glue down method.
To glue the floor down:
Firstly, ensure the subfloor is flat, free from dust and dirt and if necessary has been primed.
Working at an area just large enough to complete within 20 minutes, apply the adhesive to the floor using a notched trowel ensuring the whole surface has an even amount of glue.
Fit the new floor boards ensuring all boards have been pulled tight and have not been moved out of place as other boards have been fitted.
Leave the adhesive to dry for 12 hours and do not walk on the floor until it is fully dry.
Unlike the PVA adhesive, the flooring adhesive is very difficult to remove from the surface of the boards so ensure that any spills on the boards are wiped off immediately before the boards have dried.
Other Adhesive based fitting methods:
There are other adhesive based fitting options used to fit flooring:
1. Adhesive backed underlay
A foam underlay backed with 1 side adhesive. The underlay has a sticky side covered in a plastic film which is peeled back as the floor is laid. Envoy multi, Elastilon and Acoustalay adhesive 300/1000 are all types of adhesive backed underlay.
2. Slatted Underlay for use with adhesive
This underlay comes with narrow slats cut out – this enables the underlay to be used in conjunction with adhesive as the glue is applied in the cut-outs. The floor benefits from being glued down directly with the added advantage of having an underlay in between. This option is used when the floor is to be glued down directly but the sub floor is not completely flat.
