DIY Damp Proofing: Can You Do It Yourself?

Damp proofing is a type of moisture control to prevent moisture from passing from external into the interior spaces, usually in building walls and floors. Untreated damp can cause structural problems, but also health issues with mould growth.

Can You Do-It-Yourself?

Simply put, yes you can but there are always going to be various levels of effectiveness in any construction work undertaken by the homeowner in matters that involve repair and maintenance.

Do you have the ability, methods and tools to deal with the problem, do you understand what the many products available offer to help you find the do-it-yourself solution and lastly is it cost effective for you?

How Do I Know If My Walls Are Damp?

• A distinctive musty smell
• The appearance of mould or mildew on walls, floors or ceilings
• Walls, floors or ceilings that feel cold or wet
• Water droplets on walls
• Dark or discoloured patches on walls or plaster
• Lifting or peeling wallpaper from moisture in the walls
• Excessive condensation on windows, not just during the winter
• Rotting woodwork like skirting boards

These are just a few examples of what to look out for if you think that damp may have set in on your property. In some more severe cases you may have all of the symptoms in which case you might not want to do-it-yourself so you would seek professional advice.

Do-it-yourself damp-proofing is possible if you have some but not all of the above, and the problem may be able to be treated by yourself but should be monitored for success.

You may think that this is a problem you only find in older buildings, but it can affect any property no matter how old it is. High humidity and the moisture content of the air are factors to consider: the position of the external walls in relation to sunlight and the original condition of the brickwork and mortar can have an overriding effect on the condition of your damp problems.

However, if you have some but not all of the above the problem may be able to be treated by yourself.

What Is The Cause Of Damp?

There are a number of issues that will cause damp in your home.

• Rain penetration
• Level of site
• Drain ability of soil
• Climate condition
• Defective orientation of building
• Moisture entrapped during construction
• Defective construction e.g. joints
• Use of poor quality bricks which ultimately absorb a lot of water
• Use of Poor quality of concrete (permeable concrete)

The list is almost indefinite, but the majority of the issues will caused by those above and some are treatable as a do-it-yourself project, however you may need to call in any professional damp proofing help.

The four main types of damp are: rising damp, penetrating damp, damp caused by defective plumbing and damp caused by condensation.

Once you have determined which type you have you can take the appropriate steps to remedy the issue.

Which One Do I Have?

• Rising damp – This occurs at ground level and will spread upwards to a height of up to approximately 1 metre. The tell-tale signs are which powder or even a tide mark on the wall and skirting boards.
• Penetrating damp – This is caused by water leaking through the wall usually from a maintenance issue such as faulty guttering or cracks to the external wall.
• Defective plumbing – Possibly the easiest to diagnose as the culprit will be associated with radiators, sinks and plugholes that have leaked.
• Condensation – This is the most common cause and usually happens in moisture filled rooms such as kitchens and bathrooms. Although not entirely dependent on the seasons this does appear to be more prevalent in the winter months.

Rising Damp Treatment

Once you established that the problem is in fact rising damp then a number of treatments can be considered but ultimately the wall on both exterior and interior of the property will have to be injected using a DPC (Damp Proof Course).  

Some of the most effective DPC’s to use are damp-proofing creams that can be used by the average person on a do-it-yourself mission with the ability to use a skeleton gun and there are some useful guides online in how best to apply them How To Use Damp Proofing Cream to Treat Rising Damp (permagard.co.uk) but please always ensure you have all of the relevant tools at your disposal before starting this do-it-yourself task.

This is a process which unless you are technically skilled is best left to the professionals.

If, however you do have some relevant do-it-yourself skills and a need to save money then this is one of the most comprehensive step by step guides we can find How to Damp Proof Walls | Twistfix

Penetrating Damp Treatment

As previously explained, penetrating damp is caused by damage to the external areas of the building. Below are the most common external defects and how using do-it-yourself damp proofing can resolve the problem:

• Roof Damage: If you have the knowledge and expertise then the cracked or missing tiles will need to be replaced
• Damaged guttering and pipes: This is the most common cause of penetrating damp problems. It is a simple fix that can be carried out by yourself. Simply unblock the gutters and pipes or if there is any damage then it will need to be repaired or replaced.
• Cracks in the Render: When the render has become damaged then this will allow water to pass through. Quite often the damp would have entered into the cavity walls which can lead to more expensive solutions. These cracks will need to be patched using a sealant or a new render.
• Damaged Windows: Any gaps can be filled using relevant sealants however if the windows have become damaged over time, then these will need to be replaced.
• Porous bricks: It is normal for bricks to become damaged over a long period of time and prolonged exposure to the elements. It is important that when the bricks become porous that they are replaced as these will allow moisture to penetrate through the walls. Using a penetrating damp solution will help damp proof and protect the brickwork.

Defective Plumbing Solutions

• Pipes are cracked or damaged: Often it is the pipes we cannot see underneath flooring that are the root cause of the damp and once they have been identified they will need repair or replacement using a skilled professional like the local and brilliant Gutter Guys team.
• Drains and downpipes are blocked: Quite an easy fix using hands to clear out blockages or even some off the shelf remedies. This site Best drain unblockers UK: Top drain and sink unblocker tools reviewed – HG Duo, Mr Muscle and tools compared » Shetland’s Garden Tool Box offers a great and very comprehensive guide.
• Radiators are leaking: This will be fairly obvious as you will have the damp signs in and around the offending item. As ever a professional plumber will always be able to assist with this but if you do feel confident then one of my go to guides is this one How to Fix a Leaking Radiator | Living by HomeServe as the language used is easy to understand for the complete novice.

Condensation Damp Treatment

The best cure for this is prevention and simple things make a huge difference, like opening windows and doors, keeping the lids on pans when cooking, drying clothes outdoors (and especially not on radiators), venting your tumble dryer to the outside and yes even the dehumidifier comes into its own here.

If you already have mould on your walls and ceilings, then you need to clean it off properly.

An effective two-stage method is to start by cleaning off the mould with spray containing bleach although recently the NHS has advised to use just soapy water. These will both help remove the staining that persistent mould can leave behind.

Leave to dry overnight and then spray the affected area with an anti-fungal wash and allow that to dry. Always follow the manufacturer’s instructions and consider wearing a face mask when spraying.

Once you have cleaned the mould from walls it is advisable to paint the affected area using a mould-resistant paint which are available from most hardware stores. These will add the layer of damp-proof membrane to your internal walls via the use of chemical compounds.

In Summary

If you are confident using tools and are keen to save money then you can carry out all of the damp proofing work listed but it is important to understand that any work has to carried out to the highest standard possible and as we all know most professionals will not only offer that as part of their service but some form of trade guarantee which may prove worth more than the money you have saved by undertaking the work yourself.

This post is intended for general information purposes and any information found within should not be seen as professional advice. It is imperative that you talk directly to an RICS accredited Building Surveyor to discuss your individual circumstances.