{"id":1370,"date":"2020-11-04T08:00:00","date_gmt":"2020-11-04T08:00:00","guid":{"rendered":"https:\/\/www.kezzabeth.co.uk\/?p=3657"},"modified":"2020-11-04T08:00:00","modified_gmt":"2020-11-04T08:00:00","slug":"why-your-cellar-walls-need-to-breathe-and-why-were-not-tanking","status":"publish","type":"post","link":"https:\/\/twitsguides.co.uk\/why-your-cellar-walls-need-to-breathe-and-why-were-not-tanking\/","title":{"rendered":"Why Your Cellar Walls Need to Breathe (And Why We\u2019re NOT Tanking)"},"content":{"rendered":"


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Renovations in our old victorian basement cellar have begun, and although it\u2019s very slow progress, this is a project I\u2019m so excited to develop! So far, we\u2019ve stripped back the walls<\/a>, opened up the fireplace<\/a> and we\u2019ve even added in a window<\/a>.<\/p>\n

We\u2019ve made great headway, but we still have plenty left to achieve before it\u2019s anywhere near usable down there. One question I\u2019ve been asked a few times over the last few months is how we\u2019ll be tanking\/damp-proofing the basement.<\/p>\n

The answer is, we\u2019re not. So I thought I would write a post and explain why<\/strong><\/em>.<\/p>\n

Before I start though, I just wanted to say that I am certainly NO expert when it comes to buildings or building work in general. However, there is A LOT of free advice on the internet (not all good advice, I might add!!) and lots of different platforms you can learn from.<\/p>\n

About 7\/8 years ago when we were in the process of selling our previous home, my eyes were opened around the questionable work within the damp-proofing industry. I spent hours reading information from experts and watching YouTube videos calling out damp-proofing techniques that just don\u2019t work in period homes.<\/p>\n

I know this may all sound like a bit of a conspiracy theory against damp-proofing \u2013 but I\u2019m going to share what I\u2019ve learnt over the years and hopefully, it will at least make you think twice about certain techniques and to weigh up the different opinions before jumping down the \u201cwe need to damp-proof X-Y-Z\u201d route.<\/p>\n

I\u2019ve also linked some great sources at the end of this post where you can find more information about damp\/breathability in old homes.<\/p>\n

Period Houses are Made with Different Materials<\/h2>\n

Not all buildings are built the same way. You\u2019ve seen cottages built in a collection of various sized local stones right? And you can tell the difference between period bricks and modern bricks? These materials are all slightly different. A bit like card, paper and kitchen roll, so to speak. Same same, but different.<\/p>\n

Some bricks are softer than others and likewise, some mortars are softer than others too. Yes, it\u2019s all mortar and it all holds your house together, but the exact ingredients and ratios might be different.<\/p>\n

In period buildings, traditionally when it was built, the mortar was made from lime<\/strong>. As was the plaster, any exterior renders and even the paint. All lime-based products! And what makes lime special? It\u2019s porous, making it breathable.<\/em><\/strong><\/p>\n

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\"Victorian<\/figure>\n<\/div>\n

Breathability in Period Buildings<\/h2>\n

When victorian houses were built, they were designed for that era. They had chimneys to house coal fires to keep the house warm, cool cellars for storing food and even the single glazed draughty windows provided the ventilation a house needed. What seems like poor choices in a world of modern technology, was probably once upon a time, clever design ideas.<\/p>\n

And that breathable lime I was talking about? It allowed moisture IN and OUT of the building structure. Whether that\u2019s in liquid form, or as gas, it meant there was a balance of intake and evaporation. A natural equilibrium and the ability for buildings to \u201cbreathe\u201d.<\/p>\n

To put this into context for you, it would mean any internal moisture from drying clothes or cooking, for example, would penetrate the lime plaster and then simply evaporate back out. External moisture too, such as from rain would do the same. It would enter the lime mortar (or render) and then evaporate right back out.<\/p>\n

Those draughty windows and warm coal fireplaces acted in favour of this natural drying cycle and because of these breathable materials, water was never trapped within the building. Which meant, these old buildings did not typically have damp problems.<\/p>\n

Any moisture within the building had an escape route.<\/p>\n

The Problem with Modern Cement, Gypsum Plaster and Damp Proofing Paints on Period Buildings<\/h2>\n

Modern houses are built very differently from period buildings. They\u2019re built with much harder bricks, they\u2019re designed to be waterproof, highly insulated and with zero draughts. Basically, the exact opposite!<\/p>\n

The materials they\u2019re built with, like cement, prevent moisture from getting in or out and are NON-breathable. In theory, this may sound great, BUT when combined with period materials or within a period home, it simply doesn\u2019t work and instead, traps moisture within the building.<\/p>\n

Remember I said some bricks are softer than others? If you replace lime mortar with a cement mortar, not only will you be trapping that moisture within the building itself (as it no longer has an escape route), but it will also cause those softer bricks to deteriorate. You\u2019ll often see this where the face of brick has crumbled away (known as spalling).<\/p>\n

Similarly, if you cover lime mortared bricks with gypsum plaster or certain modern paints, (like weatherproof masonry paint which is non-breathable), you\u2019re disrupting that same natural balance and again, trapping moisture. <\/p>\n

These materials simply weren\u2019t designed for old buildings and don\u2019t work well when used with traditional materials.<\/p>\n

Check out this video<\/a> to see a real example of the effect of cement on period bricks.<\/p>\n

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\"spalling<\/figure>\n<\/div>\n

What Does Trapped Moisture Lead To?<\/h3>\n

So I\u2019ve given you a couple of examples already, but let\u2019s break it down further:<\/p>\n

Damp Patches<\/h4>\n

Where moisture cannot escape, you\u2019ll find damp patches. This might be from condensation within the home or water trapped on the outside of the home. Where it would once upon a time have simply evaporated away, it\u2019s now stuck within the very fabric of the building.<\/p>\n

Peeling Paints<\/h4>\n

Many modern paints are also non-breathable. Ever seen a Victorian house covered externally in peeling paint? When moisture wants to get out, it will find any possible way to get out. In time, the paint will flake and peel away from the surface. This is a particular problem with masonry paint.<\/p>\n

Spalling Brickwork<\/h4>\n

One of the worse effects of trapped moisture is spalling bricks. As I mentioned previously, this is when a brick is deteriorating. Usually, the face of the brick will burst off and eventually, the whole brick will crumble.<\/p>\n

This often happens specifically when moisture within the brick freezes (and expands as doing so), therefore breaks the brick. Over time, spalling bricks allow more moisture to penetrate the brick, creating more problems. Eventually, these bricks need to be replaced and many over a large span can even become a structural issue.<\/p>\n

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\"peeling<\/figure>\n<\/div>\n

What About Damp-Proofing Treatments?<\/h3>\n

There is a vast amount of different damp proofing treatments available and each work in different ways, but essentially, they act to prevent moisture from entering a building. However, if you\u2019ve read the above, you\u2019ll know this has a similar effect as cement and doesn\u2019t FIX the issue, it simply traps water, or masks over it until the moisture can find a new route to escape.<\/p>\n

Many believe the whole damp proofing industry is a con and I\u2019ve read some debate that there is no such industry in certain countries across the world. Rising damp, in particular, in a greatly debated topic.<\/p>\n

I could write a whole blog post on the topic, but there is evidence to suggest that many damp proofing treatments simply don\u2019t work in period homes and that they weren\u2019t required in the first place!<\/p>\n

There are many reasons for damp, including the external ground being too high, leaking gutters or drains and of course, things like cement being used in period homes. These issues are often overlooked when damp-proofing is advised.<\/p>\n

The Importance of Breathability In Basements and Cellars<\/h2>\n

If there was one place in your house which is GUARANTEED to have moisture within it \u2013 it\u2019s probably going to be the basement or cellar. It\u2019s underground after all.<\/p>\n

So naturally, that moisture on the outside penetrates through to some extent. Your first thought might be \u201chow can we STOP this moisture from getting in?\u201d and more likely than not, your cellar or basement will have evidence of previous attempts at stopping it.<\/p>\n

Maybe you have bitumen or another kind of damp proofing paint slathered across your walls? Or maybe it\u2019s been concrete rendered? Maybe those draughty windows and the original coal hole have been blocked up?<\/p>\n

Unfortunately, these methods have probably done very little to help the situation, and if anything, they\u2019ve made it worse, simply trapping<\/em> that moisture and saturating the brick, rather than allowing it to escape.<\/p>\n

A big problem with a basement having moisture trapped within its walls, if that the basement is the very foundations of your home and dampness in a cellar can also lead to rotten floor joists in the rooms above too.<\/p>\n

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\"dealing<\/figure>\n<\/div>\n

The Problem with Tanking<\/h2>\n

Tanking is a form of waterproofing and has many different forms. From liquid cement slurry which acts almost like render, to plastic sheet membranes forming a barrier around the wall, the list goes on.<\/p>\n

The problem with all those methods? It still traps moisture within the walls. And the problem with being underground is that it\u2019s almost like creating a swimming pool around the outside of your house.<\/p>\n

Sure it may keep the damp from displaying itself in your basement for some amount of time, but the problem is, your house is now sat in that moisture. Eventually, the bricks will saturate in moisture, deteriorate, spall and crumble over the years. You may start to find damp patches in the rooms above as moisture fights its way out, destroying joists, timber floors and other woodwork in its route. And worst yet, that higher moisture level, in time, will simply make your basement wetter.<\/p>\n

So What ARE We Doing to Prevent Damp in our Cellar?<\/h2>\n

Our plan is pretty simple. Instead of focussing on keeping moisture OUT, we plan to work WITH it, just as our home was originally built to do. This basically means putting the cellar back to the way it was built.<\/p>\n

Remove ALL Non-Breathable Materials<\/h4>\n

You\u2019ll know we\u2019ve already removed as much waterproof coating as possible from our basement walls. This includes cement slurry, bitumen paint, masonry paint etc. This will allow the walls to breathe again and for the moisture to escape.<\/p>\n

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\"the<\/figure>\n<\/div>\n

Improve Ventilation and Air Circulation<\/h4>\n

Ventilation and good airflow is key to keeping a basement dry. You\u2019ll know our basement had ZERO ventilation and we\u2019ve already tried to improve that slightly by reopening the bricked-up window<\/a> and reopening the fireplace<\/a>. This will allow fresh air into the basement and to some degree, the open fireplace will allow a route for air to move out of the basement.<\/p>\n

This certainly isn\u2019t fool-proof though and in an ideal world to improve circulation, we\u2019d add a mechanical ventilation system to guarantee good air movement. At the moment, we\u2019re not doing this \u2013 but we\u2019re mindful of this being an option should we encounter moisture issues.<\/p>\n

It\u2019s worth noting that adding a load of external vents does very little for damp, it simply allows cold air in. Ventilating a basement and then circulating that air is two separate issues. <\/em><\/p>\n

We could also add vents in the floorboards of the rooms above (nice decorative ones of course!), but again, this is something we\u2019ll consider down the line should we need it.<\/p>\n

Install a Dehumidifier and Radiators<\/h4>\n

On top of ventilating and circulating, we\u2019ll also be adding a dehumidifier to collect excess moisture (again, this will allow us to manage moisture rather than prevent it) and some radiators too. This will replace cold air with warm air, which is also a key element for keeping a basement or cellar dry.<\/p>\n

You can get mechanical ventilation systems which will warm cold air at the same time as removing moisture and providing air flow, however, these systems are quite pricey, so for now, we\u2019ll just be using radiators and a dehumidifier.<\/p>\n

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\"electric<\/figure>\n<\/div>\n

Use ONLY Breathable Materials<\/h4>\n

Finally, we\u2019ll be using traditional breathable materials, such as lime mortar, lime paster, quarry tiles (made from clay and are breathable), lime wash and\/or clay paint. All of which will allow moisture in\/out.<\/p>\n

Will that make our basement dry? Hopefully, yes \u2013 it\u2019s all a bit of trial and error, but we\u2019ll certainly find out and I\u2019ll keep you posted!<\/p>\n

I know some houses which have a serious damp problem in their cellar basements often use additional pumps\/drainage systems to manage moisture, but debatably amongst many experts, tanking should very rarely ever be required.<\/p>\n

Word of Caution Around the Word \u201cBreathable\u201d<\/h3>\n

The last thing I wanted to mention on this post, is that I highly recommend thoroughly researching any products you find which claim to be \u201cbreathable\u201d.<\/p>\n

The problem is, as more people are understanding the need for breathability within period homes, more companies are launching \u201cbreathable\u201d products. Great, you\u2019d think! Except, HOW MUCH a product is breathable may greatly vary.<\/p>\n

Imagine buying a \u2018pork\u2019 sausage, which is only made up of 5% pork. If the sale of meat was unregulated, it could claim to be pork even with just 5%. But compared to a 95% pork sausage, it\u2019s not really a match, is it?<\/p>\n

Some breathable products are just like that. According to experts, the term \u2018breathable\u2019 is currently unregulated and HOW MUCH a product is truly breathable may greatly differ. A product that claims to be \u201cbreathable\u201d may not be nearly breathable enough.<\/p>\n

My advice is to research well, find reviews and invest in longstanding reputable brands known for their traditional materials.<\/p>\n

For more information, please read this in-depth article<\/a>.<\/p>\n

Read What The Experts Have To Say\u2026<\/h2>\n

So there you have it. Everything I\u2019ve learnt about period buildings and breathability over the years. Don\u2019t take my word for it though, check out some of these sources for more information\/advice on damp and traditional lime products:<\/p>\n