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A DPC (damp proof course) is a legal requirement in all residential properties in the UK. In modern properties you will either have a rigid DPC or a flexible DPC.
Flexible DPC’s are usually a plastic sheet that is placed in the mortar joint between bricks, roughly 150mm above external ground level. This is the most common type of damp proof course installed in new build properties.
Engineering bricks can be used as a rigid DPC. This consists of two or more courses of Class A engineering bricks. This type of brick has the lowest absorption of any clay brick produced in the UK, which means it is very resilient to rising damp.
Absorption in Class A engineering bricks is around 3.5%, compared with standard clay bricks which can be anywhere from 12-20% (even higher in old bricks).
Are engineering bricks damp proof
Engineering bricks are not completely damp proof. However, they do have very low absorption compared with other bricks. This means that they are often used in areas where there is the potential for water and frost.
Unlike a plastic DPC, they will take on small amounts of moisture, but this is very minimal, and they are quite capable of holding off rising damp. The bricks would need to become highly saturated, over a long period of time to allow water through. Even then it is not likely.
Because they don’t hold much water they are also not at risk from frost. Other bricks that have higher absorption, can be easily damaged by frost/thaw cycles. This happens when a brick is saturated with water and the water freezes. As water freezes it expands and this can cause bricks to crack.
Engineering bricks have two advantages in this regard:
- They are much tougher than standard house bricks
- They are far less permeable to water
So, whilst not completely damp proof, they do offer excellent protection from damp. For this reason, engineering bricks are used in various situations where high moisture and frost is an issue. This includes several jobs carried out by civil engineers, such as places like manholes and sewers
Why are normal bricks not damp proof?
Normal building bricks, such as facing bricks are not damp proof. This is due to them being a less dense and more porous. An engineering brick has much higher compressive strength, which makes it far more resistant to moisture.
Standard bricks do not fare very well below DPC level (150mm). You can quite often see this in properties with a plastic DPC or older materials used in older properties. Generally, the DPC will be in the mortar joint a couple of courses up. Here you will quite often see clean undamaged bricks above the DPC and much more damage below.
efflorescence on brick is common, as ground water rises it brings salts from the ground below. Due to the bricks being so porous, they become saturated. Following this a powdery residue settles on the face of your bricks.
Also, when water freezes inside bricks, the expansion can cause them to crack. It is not uncommon for the faces to completely fall off. This is known as brick spawling. These are problems you will not face with engineering bricks below, and up to your DPC.
Advantage of engineering bricks over other types of DPC
There are several advantages to engineering bricks, over a plastic DPC. One of the main advantages, is they are less likely to fail or be installed incorrectly.
It is very easy for a plastic DPC to become damaged during installation. A little tear, or rip can be all moisture needs to travel higher. It is also easier to leave gaps and position the plastic DPC poorly. When either of these happens, you are leaving gaps for rising damp to pass through.
Poor installation is one of the biggest causes for failed DPC’S. Once it has failed, it can be a big job to replace. Even if you choose an injectable damp proof cream, which is easier to install, it is still messy. Plus, you may need to replace plaster rand redecorate once the job is done.
The advantage with engineering bricks, is they are solid bricks. It is far less likely that engineering bricks will be installed badly.
They also last longer. In theory a brick DPC should last forever, whereas a plastic one will generally have a lifespan of 20-25 years.
Need help installing your DPC?
If you are considering installing engineering bricks as a DPC, then you would probably benefit from the help of a professional. This is especially true if you are repairing an existing DPC and need to carry out structural work. A damp company will have qualified bricklayers who can carry out this work safely and correctly.
This type of work should only be carried out by a fully insured professional, with experience in this type of work.
The best way to find good tradespeople and view all their credentials, is through comparison sites. Here you can look at their past work and read customer reviews. This means you will hire someone who knows what they are doing.
Also, you can save a lot of money this way. All the tradesmen on these sites are competing against one another. We often see savings of 30-50% by comparing this way.
To get help with your DPC, you can compare damp proof companies by Clicking Here