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Have you noticed that the paint is coming off the walls? Has a wet spot appeared under the windowsill? Have you tried painting it over and over again but it keeps peeling off the walls? Perhaps you have decided to bite the bullet and call in a waterproofing expert for advice? That’s a great idea, but it’s better to know if the waterproofing expert is giving you the right advice. It could be a costly and time consuming mistake if he doesn’t know how to buffer the test in theory.
Now let’s take a quick look at how to waterproof, what to look for, moisture proofing products available, and how these moisture proofing products and systems can solve your moisture problems.
So first we need to identify the wet areas of your work and what is causing them. Now this can be tricky, but we can remove some obvious moisture proof items before you pay to have someone come and consult us.
Damp walls high up or in a secluded area? Does the wet area manifest internally at a high level? Check the exterior for condensation overflow or toilet overflow pipes dripping onto the drywall. The constant source of water against your brick work can reach your internal finishes and manifest as a wet patch or seeping salts. This should go without saying, so stop it right away and then once you’ve done it, it’ll just be a matter of redecorating your damp wall. Another culprit here is the leaky gutter or down pipe, same again, stop the outside source of moisture and your problem should be fixed. Damp walls can also be a problem, and water ingress into your property can also be caused by structural defects. This is harder to determine, so here are a few things to look for: Chimney flashing or other lead flashing under windows Cracks in walls – may need structural repair – consult an engineer Poor pointing – could be a major problem – needs professional advice Loose tiles – obviously need instant source of moisture in structure, bridging a cavity wall with debris
All of the above, except for the cavity wall bridging, can be visually verified as a source of moisture problems. However, it may be worth making sure you get a full report from a chartered surveyor.
Another problem you may encounter is condensation mold caused by lack of ventilation in the property. Usually found behind cabinets or in corners, condensation problems look like black dots and can easily be mistaken for rising damp. Again, ventilation is an expert job and modern properties that are governed to be more airtight suffer as a result. A qualified surveyor should be able to tell you the direct right here as with structural defects.
The biggest problem in moisture proof diagnostics is high soil levels above the existing moisture test layer or the lack of a moisture test layer in the first instance. If you have high external soil levels, then you need to lower them; otherwise you could be dealing with more than just damp walls, in the worst case scenario you could have water coming onto your property. If you can’t remove the soil, you’ll need to use a waterproofing technique just like you would in a basement.
Now that we’re getting an idea of where the moisture might be coming from, let’s look at “how to do a moisture test” with the knowledge we just gained.
What is moisture proof course? How do I deal with my property if it is not working or does not have one?
In the guide “how to do a humidity test” this is the first point that should be established. Do you have a moisture-proof course and what to do if you don’t? Damp Proof Layer or dpc is a physical barrier, either slate on older properties or on newer properties, it is a hdpp or hdpe membrane approximately 150mm thick and situated above internal floor levels inserted into the mortar layer 150mm above external floor level. This dpc is an essential part of the construction and prevents moisture from rising (moisture rising from the ground) and manifesting as moisture internally in its structure.
If your dpc is down or missing, you will need to reset it or install a cavity drainage membrane to deal with moisture internally. To reset the dpc, you can either physically cut it into the mortar bed and replace it with a slate gasket (an expert works with a few with the skills to do this task) or, more commonly, insert a chemical dpc. The insertion of a dpc is the job of a waterproofing specialist. Insertion is achieved by drilling holes in the exterior, usually about 20cm apart, to the appropriate depth for your wall and injecting a moisture proof liquid or cream to form a barrier preventing moisture movement. Technology has advanced with the advent of DPC creams, which tend to be a better option than other liquids, but be warned, they are not foolproof and must be installed by someone with the proper training. Insertion of creams or liquids can be complicated and time consuming as it involves ‘cutting’ the wet plaster to a height typically 1.2m prior to injection and then re-plastering with a salt retarding additive in the mix to prevent salt bleed through afterwards. The real issue here is the wet trade and drying times involved before you can go and redecorate. Ask the contractor doing the moisture testing work what form of warranty they will give you, as different schemes vary.
The next option on how to waterproof is to use a cavity drainage membrane. These membranes are dimpled sheets that can receive a direct plaster or plasterboard finish. This type of waterproofing is a physical barrier that is mechanically attached to the interior and the air gap allows the wall to “breathe” so all the moisture can escape without staining or guessing what the cream alternative offers. Therefore, it acts as a barrier to the covered surface area, not just a line across the mortar joints. This waterproofing material can also be used externally to prevent rain or moisture from penetrating or penetrating through porous bricks, faulty mortar layers. Cavity drainage membranes on the market range in dimple thickness from 3mm to 8mm. These products will cover all the bases in terms of not allowing moisture to affect internal finishes and can be applied with minimal surface preparation and little to no drying time. However, you will need to identify the source of wet walls (such as faulty gutters) for the good of the overall property.
So I hope you now have enough information to go off and learn the first steps of “how to test for moisture”. You have many weapons at your disposal; it’s all about getting the right advice and the right contractor to help you choose the option that’s perfect for you.