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Can I Install a Damp Proof Course in an Older House?

14 November 2023

Damp proofing is often a problem that people don’t really think about – that is, until its too late and the damp has set in. This can be especially true in cases where the property is older, and maybe the damp proofing is as ancient as the property itself.

So, in cases where you might own an older property, what can be done to install a damp proof course in an older home?

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What Does a Damp Proof Course Do?

Timberwise engineer kneeling injecting a damp proof course into a wall

 

A damp proof course is, very simply put, a layer within a properties masonry or overall construction which serves the express purpose of stopping damp from rising any higher, into a properties walls.

Because the type of damp that a damp proof course is combatting is rising damp, a damp proof course will usually be inserted in a property just above ground level. You can usually see it if you look at your properties walls from the outside.

Just above ground level you might notice a membrane between the layers of bricks, or more commonly a line of dots, or drilled holes, which have been filled with either the damp proof course injection cream, or a treatment of damp proofing rods.

Either way, the purpose is the same: To stop moisture travelling upwards within your properties walls and brickwork via capillary action from presenting as damp at a visible level within your property.

If you are looking at your property, and have noticed that you are still seeing rising damp despite a damp proof course or membrane being present, then its entirely possible that the DPC has failed, and you may need to have it looked at.

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Why Doesn’t My Property Have a Damp Proof Course:

Signs of Rising Damp on the outside walls of a home

 

Damp proof courses and membranes are all commonplace in modern homes, but the practise of having a damp proof course actually being a part of the construction process for a property wasn’t actually commonplace until around 1875.

Don’t think that this is when damp proof membranes or injection foam was invented either. In 1875, it became mandatory to include a damp proof course in any new property being built in London, but this often meant the introduction of a layer or two of slate within the brickwork, with that slate acting as the DPC at the time.

This was an effective solution when installed, but over time this slate would break causing the early DPC to fail and require either repair, or more likely, replacing.

So, it’s commonplace for older properties to bear the mark of modern damp proofing as a result (those drilled out holes we mentioned before for example), but they may not be a uniform solution found across all older properties.

In fact, you may well be in possession of an older property that has managed to avoid any form of damp proof course being installed throughout its life, and the signs of rising damp becoming more prevalent during times of the year when rain is more plentiful could be your indication that a new DPC needs to be installed.

Basically, if you own an older property, don’t take it for granted that it comes complete with an active, working, and modern DPC. If you are unsure about your properties DPC status, then you can always have one of our professionals take a look via one of our PCA backed damp and timber surveys.

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Worried about rising damp?

Can I Install a Damp Proof Course in an Old House?

Closeup of rising damp appearing on the exterior wall of a property

Yes.

If you own an older property, even a listed property, there are DPC options available to you to help reduce and control the amount of rising damp that could be affecting the property.

If you own a standard, brick-built older building, then the installation process is fairly straightforward.

One of our surveyors will visit to assess your properties need for a damp proof course, and outline their recommendations to you in a comprehensive report. Then, once you have agrees to the works outlined in the report, one of our technicians can visit your property, and begin the process of injecting our damp proof cream.

This is the most efficient method of installing a DPC, and it involves our technician drilling holes into the mortar joints, which are then filled with our damp proof injection. This cream will then create a waterproof barrier past which moisture cannot rise, creating an effective damp proof course in your properties walls.

Of course, this is the optimal solution, but that doesn’t mean there aren’t other options available.

Sometimes, a property may need a less invasive touch, and this is definitely the case when it comes to listed buildings. If it is difficult to get the approval to make the kind of invasive changes to a listed buildings walls necessary to allow for the injection of a DPC, then we can always facilitate the installation of an electro-osmotic damp proof course.

This is a version of a DPC that works differently to an injected cream, as it involves a series of titanium wire anodes affixed to the wall which apply a low level of static electricity, which discourage capillary action.

This is a chemical free solution, using about as much electricity as a low voltage doorbell, and it has proven effective in listed buildings in the past, and can always be explored as an option if a chemical DPC injection isn’t viable.

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Concerned about damp in a listed building?

How Much Does a Damp Proof Course in an Old House Cost? 

A damp, stone wall

The cost of a DPC being installed in an older property depends entirely on the size of the property, and the type of DPC actually being installed.

We cannot recommend enough that you have a DPC installed by a professional. Not only will this ensure that the DPC will be installed in the older property correctly, but when carried out with a PCA-backed business such as Timberwise you will be safe in the knowledge that the work is all in line with PCA guidance, and will come complete with a guarantee, potentially saving you money in the future.

When you have your surveyor’s report delivered to you following your survey, it will include a price for the DPC to be installed by a professional. What is worth noting though is that its rare for a properties age to be a significant factor unless the property is in fact listed.

If you are concerned about the lack of a DPC, or new rising damp appearing in a property that you own, then you can always organise a survey from our team by calling 0800 288 8660, or by filling in the form below.

We will be happy to help you understand more about your property and it’s current damp proofing provisions, as well as help you understand what kind of DPC installation it might benefit from.