Damp in Concrete Floors

Concrete floors are susceptible to moisture rising up from the ground through the capillaries of the concrete, this process is known as capillary action. Concrete is made up of a mixture of cement, water, and aggregates such as sand and gravel. When concrete cures and the moisture evaporates it creates microscopic pores and channels making the structure become porous.

In principle all concrete floors should include a damp proof membrane (DPM) and this should be connected to the damp proof course in the surrounding walls to provide continuity of protection against ground moisture. It can often be the case that concrete floors were not installed to modern building standards and do not incorporate an effective DPM. This means there is no barrier to prevent moisture rising up through the floor.

The absence of an effective DPM which is correctly finished at the wall-floor joint intersections is likely to result in ground moisture permeating up through the floor construction creating a damp environment. This can lead to the surface of the concrete structure becoming damp, which in turn can damage carpets or lead to warping laminate flooring and wooden floors.

If you are worried about a damp in your floors, Peter Cox can provide a professional damp and timber survey to identify where the moisture is coming from.

Peter Cox can as part of a damp survey inspect damp concrete floors within a property. They will carry out a visual inspection to ascertain the possible source of moisture within the floor and if the existing solid floor construction would not appear to meet modern building standards.

The surveyor will also take time to check the condition of structural timbers, especially if they are in direct contact with the damp concrete, to make sure no fungal decay or woodworm is present. If the concrete floor is below ground this could require a more specialist waterproofing survey.

A thorough survey is essential as damp issues can be more complex than meets the eye. Our Surveyors have years of experience and will come to the correct diagnosis using specialist tools and equipment, and will make sure nothing is missed.

Due to the porous nature of concrete and other substrate moisture is able to rise through the capillaries and into the premises. This is usually prevented by a waterproof barrier, typically a damp proof membrane (DPM) put in place during the building process. However these membranes can become damaged or were not installed properly, or not installed at all.

Other factors may include changes to external drainage outside, or if they have become blocked causing the immediate area to be saturated with water. Leaking pipes or damaged drains can cause moisture problems under floors.

Environmental factors such as prolonged rainfall and periods of consistently damp weather may increase ground water levels. Even changes to landscaping, such as the removal of a large tree can affect ground moisture levels that can intern put pressure on the property’s structure leading to moisture ingress.

Signs you could have damp in your floors if you notice:

• Damp patches
• Visible waterstains
• Discoloration
• Musty smells
• Salty deposits known as efflorescence
• Damage to floor coverings
• Mould growth on floor coverings

If you have a confirmed damp problem in your concrete floor, there are options available to solve the problem.

The first option is to fully replace the floor by digging up the old concrete and correctly installing a new damp proof membrane.

This can be labour intensive, costly and disruptive. There are other remedial options available.

A slim but tough damp proof membrane can be laid on top of the existing concrete slab which can be connected to existing damp proof courses, isolating the slab from and creating a waterproof barrier.

These membranes are also used as part of basement waterproofing specification and are designed to be tough, hard wearing and watertight.

You may need a professional survey carried out by an experienced surveyor to determine if this is a suitable solution and provide you with a specification.

Another option is using an epoxy resin coating which is applied across the floor surface to create a waterproof seal and prevent further moisture ingress.

This is a simple treatment that simply requires the floor to be cleaned and prepared and the removal of any existing floor coverings.

You should have a professional survey carried out by an experienced surveyor who can advise you on the effects of hydrostatic pressure through an installation of this type of barrier.

Without a complete solution moisture may continue to enter the property, a damp survey will provide information on any existing damp proof courses, or if further rising damp treatments are required for walls.

If you are worried about a damp problem in your property, Peter Cox can provide a damp survey from trained professionals who can offer advice and recommendations for long term peace of mind.

Peter Cox have a network of local branches all across the UK so a team of qualified surveyors and experienced technicians can be on hand to help.

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  How to fix damp concrete floors?

  The only way to fix a damp problem in a concrete floor is to identify the source of moisture and understand where it is coming from. If the concrete floor has no damp proof membrane, or is damaged, you may need a professional to carry out remedial damp proofing.

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  How to stop moisture on concrete floors?

  To stop moisture on a concrete floor you first need to understand where it is coming from, whether it's a condensation problem, or damp rising from below. If it's a rising damp problem  a possible course of action is applying a waterproof barrier, either through the use of epoxy resins or membranes. However this type of treatment can in certain circumstances bring attentional pressure on the structure so it is important to seek the advice of a trained surveyor who will be able to help identify the source of moisture and provide appropriate  recommendations.

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  How do you dry out damp concrete floors?

  Improving ventilation or using a dehumidifier will help dry out a damp concrete floor, however this is not a solution for the root cause of the problem and will not fix it long term. A damp surveyor will be able to help identify the source of excess moisture and provide recommendations.

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  Can you put a damp proof membrane over concrete?

  Yes, you can use a damp proof membrane (DPM) over concrete, this is a common procedure if you do not wish to fully replace a concrete floor. This method is sometimes used for basement waterproofing using tough and durable floor membranes.

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  Do you need a waterproof membrane on a concrete floor?

  This depends on whether or not the problem is caused by rising damp. If there is already an existing damp proof membrane from when the floor was built, it may not be needed and would indicate damp is coming from elsewhere, such as a condensation problem. A damp surveyor will be able to help identify a problem.

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  What can I put on a concrete floor to stop damp?

  A damp proof membrane can be installed on top of a concrete floor to help stop damp rising up into the property. Walls may also need damp proofing if no damp proof course exists.

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  What is the best moisture barrier on top of a concrete floor?

  A damp proof membrane is considered one of the most cost effective and least intrusive ways to create a waterproof barrier on top of a concrete floor.

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  How to get rid of damp through concrete floor?

  To get rid of damp, you first need to identify the source of moisture, as the solutions depend on how the moisture is being produced. Ventilation improvements may work for a condensation problem, but if damp is rising through porous concrete, a damp proof membrane may be required.

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  Why is water coming through my concrete floor after it rains?

  If moisture is coming through a concrete floor after it rains, this would indicate the absence of a damp proof membrane, so the groundwater is able to rise up through the porous concrete through capillary action. Another reason could be that drains that are meant to take away rainwater may be blocked, and water is backing up. A damp surveyor will be able to help you identify the source of the problem.