In an ideal world damp proofing methods should be taken during the initial construction phase of the garage.
Damp proof concrete garage floor.
Damp proof membranes are routinely used during the construction of a concrete floor.
All seemed good and it dried well.
Most damp proof floor coatings are applied directly to the concrete floor.
This is because damp rising up through concrete floors is a pretty common issue.
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.
Floor membrane from property repair systems roll out and lay on either chipboard plywood mdf or screed.
However typically these are often fairly thin and are sometimes damaged even before they are laid.
Sometimes the issue can be bridging of the damp proof course by the concrete floor assuming is was timber prior as this often occurs.
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.
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.
It could also be bridging by the internal plaster or a failure of the wall floor joint.
When faced with damp in concrete floors there are two options available.
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.
This can cause issues with mold and mildew especially if you have carpet or.
Concrete s porous nature means that water from under your home can seep up through your concrete floor making it damp.
I m guessing that this sheeting is the vapour barrier you talk about.
Damp in concrete floors are much more difficult to treat than having damp walls.
Damp affecting concrete floors.
How to damp proof concrete floors.
I suggest you get an independent survey to pinpoint the problem before undertaking any remedial works.
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.
A damp proofing concrete floor solution is particularly important.
Fully isolate the dampness in the floor using a surface damp proof membrane dpm damp proofing concrete floors above ground damp proofing for extensions.
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.
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.
Damp proof membranes for concrete.