Sometimes the issue can be bridging of the damp proof course by the concrete floor assuming is was timber prior as this often occurs.
Damp proof concrete garage floor.
Damp proof membranes are routinely used during the construction of a concrete floor.
I m guessing that this sheeting is the vapour barrier you talk about.
Concrete s porous nature means that water from under your home can seep up through your concrete floor making it damp.
The damp proof membranes used during construction of concrete floors are often thin and can easily become torn before they are laid rendering them.
However typically these are often fairly thin and are sometimes damaged even before they are laid.
This can cause issues with mold and mildew especially if you have carpet or.
When faced with damp in concrete floors there are two options available.
Dig up the old concrete floor install a new damp proof membrane and lap up edges before replacing the concrete slab.
After the construction was finished i painted the concrete floor in the new extension.
Damp proof membranes for concrete.
Fully isolate the dampness in the floor using a surface damp proof membrane dpm damp proofing concrete floors above ground damp proofing for extensions.
When damp proofing a concrete garage floor a plastic dimpled membrane is required if the floor is going to be boarded either with chipboard plywood or similar or if a concrete screed is going to be laid.
Most damp proof floor coatings are applied directly to the concrete floor.
All seemed good and it dried well.
Floors can easily suffer from moisture ingress otherwise known as penetrating damp.
But if these methods are non existent or if they have failed in some way here are some ideas to resolve and reseal your damp garage floor.
Damp rising through concrete floor slabs is fairly common causing damp issues on carpets and floor coverings warping wooden floors and increasing the likelihood of low level mould growth.
I believe a damp proof sheet was used under the concrete floor as indicated by the telltale black sheeting used before the concrete floor was poured.
In an ideal world damp proofing methods should be taken during the initial construction phase of the garage.
Damp affecting concrete floors.
Floor membrane from property repair systems roll out and lay on either chipboard plywood mdf or screed.
There are however two options for damp proofing concrete floors without needing to replace the floor itself.
I suggest you get an independent survey to pinpoint the problem before undertaking any remedial works.
Damp in concrete floors are much more difficult to treat than having damp walls.
It could also be bridging by the internal plaster or a failure of the wall floor joint.
Either a damp proof coating can be applied to the surface of the concrete or a damp proof membrane can be laid on top of the concrete.
The reason for this is that concrete is a very porous material meaning that water can rise through capillaries and therefore lead the property to suffer from having damp floors.