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Our first clay plaster & wall heating

Whether you are looking for a joined family-construction-project or thinking about replacing your heating radiators: we highly recommend you clone our latest (& unfinished!) renovation hassle!

Wall heating – what it is and how it fits in

Since I did not hear of a wall heating before my hubby introduced me extremely enthusiastically and nor did any of our friends, I first want to explain a bit…

My personal summary would be: think of a floor heating (hot water, not electrical) that you mounted to the wall.

The wall heating itself is made up of so-called ‘Climate Grids’: orange-coloured pipes are bent for customization and then embedded in clay or lime plaster. They are suitable for heating and cooling.

Because of the dimensions, we could make use of a pre-assembled component; the pipes are bent to spirals, aligned in parallel and fixed on toothed rails; for one of the two walls. For the other wall we had to personally measure and bent the pipes which was very much of a headache (even though worth it).

The pre-fitted grids mounted to the wall

After the Climate Grids or Climate Pipes have been completely installed, connected and pressure tested, plaster is applied in several layers. To provide some structure for the clay to hold on to, reed mats were added between the wall and the grips before going ahead with the plastering.

Now, why would you do that?

  1. First of all, we did not want to remove the flooring (old terracotta/saltillo tiles which we have throughout the house) because of the hassle and dirt, not being able to source matching tiles again and because of the different floor level. But also, since this specific project was for our bedroom only, surrounding the bed-corner with a nice warm wall just appeared to make more sense than heating the whole floor and room.

  2. Since the pipes are being covered with plaster, there is no radiator visible in the room. Which makes for much better aesthetics but also gone are the days of the painful and time-consuming cleaning process etc.

  3. This heating system reacts very promptly because it is so close to the wall surface and the warmth is felt immediately (no need to first have all of the cold radiator metal warm-up before benefiting from any heat).

  4. The system is based on thermal radiation rather than on hot air. In contrast to other heating systems the wall heating hardly produces any airflow. The room air is, therefore, less dry and less dust circulates in the room (not that we would have any, to begin with 😉 ).

  5. It can be used for cooling as well!

There are more good arguments to be made – but I’m not getting any wall heating sales commissions so I will leave it with the reasons that mattered most to us.

Clay plaster

We are both very big fans of the idea of natural building and have visited impressive cob houses, houses with clay or lime plaster and have been amazed.

However, because of the warnings from others (in person, on youtube, you name it), we were interested yet were sure to leave this task to an expert. So we started searching. Locally, then countrywide, and abroad. Experts on this are rare and all seem to be overbooked and very expensive. We, therefore, sighed relieved when we found a Greek couple who are delivering excellent cob, clay and lime works throughout Europe and agreed they could get the plastering job done on their return route from another project in Austria. However, the timing did not work out after all (scheduling wise but also because of materials to be delivered from abroad).

Clay plastering – more local and hands-on than we intended

Winter approaching, the wall heating installed but not plastered, we had to take action ourselves. The worst thing that could happen, the whole clay plaster would crumble and mess up the bedroom and we would start all over again… Well, to make things even trickier (+ more fun for our little one + more unbelievable for visitors): we weren’t able to import sufficient amounts of clay from abroad and had – yes, seriously – start digging for clay in our yard. Based on previous tree plantings we knew the soil quite a bit and were very optimistic to find enough. And we did!

The first load of freshly dug up and sifted back yard clay

Our little one quality-checking her precious harvest

To get an idea of the consistency and feel of the ‘correct’ clay plaster, we first added the suggested amount of water to the purchased clay plaster and followed the instructions:

The dry mix – clay, sand and straw

After adding the water and mixing well – this plaster is ready to be used!

We then tried to replicate with our home sourced materials and got something very similar indeed. But would it work? We gave it a go – all of us. And with the little one’s shovels because she insisted on that in such a cute way:

Our first homegrown and homemade clay plaster <3 (Apologies for this picture taking up so much room – but I wanted to show the proof of all the hard digging work: see the little roots?? 😉 )

First bit of plaster on the wall…

And yes, we were applying the plaster with play shovels. And it was much fun and play time with the little one indeed

It felt completely playful and I personally was very doubtful that this mud party would turn into a functional and sustainable wall, but at least it was a great project with the little one and a great lesson on natural building. Also, words can’t describe her excitement and how proud she was to be a vital part of this project! No messing with the mud from her end, she liked the play but was very serious and careful about it.

The clay has to be applied in several layers to avoid cracks and the total plaster coat to embed the wall heating components is approximately 35 millimetres thick.

Why we are fans of clay plasters

Clay plasters are permeable to vapour diffusion and capillary active. Therefore, the absorption and transfer of humidity do not harm them in any way. Mould formation and moisture damages are considerably reduced. And being a natural product (literally out of our fruit orchard) it is completely free from emissions.

One major benefit of clay plasters is their sorption capacity, i.e. their ability to absorb humidity contained in the indoor air and give it off again when the air gets drier. Moreover, clay can absorb smells and pollutants! It is really quite magical and the feeling of a warm clay wall is hard to describe without sounding a bit voodoo 😉

And since the plaster is essentially garden dirt, think about it: Whenever a mistake is made (high likelihood because of us being novices!), we just add water. And like the garden soil outside, the clay will soften again and corrective work, removal etc. is super easy (as is the cleanup – just a bit of garden soil on the floor & clothes is our daily status quo anyway).

Summary and conclusion – part one

We still did not finish the project! Life got in the way and since we got the wall heating to a level that was functioning well for us and is not crumbling away, we had to take care of other more pressing todos.

At the current stage, we still need to 1) Fill some gaps around the newly installed power outlets and light fixtures, 2) Apply the finishing layer (a purchased finer finish-clay-plaster) 3) come up with construction to hide the main connection of the heating pipes that are coming out of the ground and the wall heating 4) add a (wooden?) border on top of the bigger wall heating grid for a smoother transition to the original wall and 5) take pictures, write another blog post focusing more on the appeal of the finished clay wall and the ultimate conclusion.

But already at this point, we can say for sure, that it was an intense but fun family project and that building with natural materials got us hooked! Don’t be afraid to start something similar – it is really just a bit of dirt and remodelling and correction is easy. Most countries by now have a great choice of clay products available. And from our experience, the sellers of those have been extremely supportive and instructive.

Also, the wall heating itself lived up to all promises. You can feel the warmth almost instantly after turning on the heating. The wall keeps the warmth nicely and feels like a warm blanket, despite running with water on a lower temperature than a typical heat radiator. If there wasn’t so much other stuff waiting, we already had a second one installed in our living room, seriously!

Want to see the end result? Make sure to keep an eye out for the follow-up post 😉


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