ᐅ Vertical clearance between gravel bed / splash guard and plaster facade
Created on: 15 Mar 2022 10:55
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Dirk__82Hi,
I have a plaster facade. The base is insulated. The exterior wall is timber frame construction, sealed at the bottom where it meets the foundation slab. I received an addendum from my house builder regarding the base detail. It recommends maintaining a vertical clearance of at least 15–30 cm (6–12 inches) between the gravel bed and the lower edge of the exterior wall. However, I’m more familiar with simply piling gravel up to the desired height and that being sufficient.
For example, in the terrace area, the paving is flush with the ground. Following the above recommendation would mean a trench running around the house on both sides. I mainly want to understand WHY the 15–30 cm (6–12 inches) clearance should be maintained. Unfortunately, this is not explained, and the builder just refers me back to this addendum without further explanation. Is this mainly about splash water (dirt)? I don’t think it’s about moisture, because 1) water drains away, 2) the plaster acts as a seal, and 3) it is also sealed at the bottom.
I would also appreciate hearing from others who have plaster facades on how they solved this and whether any issues have arisen from simply piling up the gravel.
I have a plaster facade. The base is insulated. The exterior wall is timber frame construction, sealed at the bottom where it meets the foundation slab. I received an addendum from my house builder regarding the base detail. It recommends maintaining a vertical clearance of at least 15–30 cm (6–12 inches) between the gravel bed and the lower edge of the exterior wall. However, I’m more familiar with simply piling gravel up to the desired height and that being sufficient.
For example, in the terrace area, the paving is flush with the ground. Following the above recommendation would mean a trench running around the house on both sides. I mainly want to understand WHY the 15–30 cm (6–12 inches) clearance should be maintained. Unfortunately, this is not explained, and the builder just refers me back to this addendum without further explanation. Is this mainly about splash water (dirt)? I don’t think it’s about moisture, because 1) water drains away, 2) the plaster acts as a seal, and 3) it is also sealed at the bottom.
I would also appreciate hearing from others who have plaster facades on how they solved this and whether any issues have arisen from simply piling up the gravel.
M
Myrna_Loy15 Mar 2022 12:40The water drains away, but moisture can remain for longer periods and penetrate the plaster. Sooner or later, the plaster will develop cracks, start to flake off, and moss and algae can grow easily.
My recommended reading for you (and for other readers of this thread) are: https://www.hausbau-forum.de/threads/bodenplatte-sockelhoehe-vermessung.42114/#post-546969, https://www.hausbau-forum.de/threads/grundriss-bauen-leichten-hang-nicht-genug-fuer-keller-wegen-aushub.42583/, and https://www.hausbau-forum.de/threads/sockelabdichtung-gemaess-technischer-zeichnung.42700/ – these have already covered the topic from all angles…
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KingJulien15 Mar 2022 16:14The BDF will likely know what they are writing about.
The joint between the base coat and the exterior wall plaster is probably OKRFB in your case as well. The wooden structure usually rests on this, relatively unprotected.
Thanks to the drip edge, rainwater cannot get in there. If you fill it up now, water might splash into the ventilation gap and possibly no longer dry out. Gravel also retains water very well! Try reaching deep into a gravel pile that feels dry on the surface.
I followed the instructions and leveled the strip at the terrace with a (not exactly cheap) metal grate.
The joint between the base coat and the exterior wall plaster is probably OKRFB in your case as well. The wooden structure usually rests on this, relatively unprotected.
Thanks to the drip edge, rainwater cannot get in there. If you fill it up now, water might splash into the ventilation gap and possibly no longer dry out. Gravel also retains water very well! Try reaching deep into a gravel pile that feels dry on the surface.
I followed the instructions and leveled the strip at the terrace with a (not exactly cheap) metal grate.
Dirk__82 schrieb:
2) The plaster acts as a sealant.No, and that is exactly why the facade needs to be protected from moisture coming from below.Take a look here to see where plaster has already started to fall off after just a few months or years because it absorbs moisture (from below).
As others have already mentioned, this is about preventing water accumulation.
By the way, this is not just a recommendation from the BDF or similar organizations, but a DIN standard requirement, and it applies not only to plastered houses but also equally to brick-clad houses. Many simply do not do it the way that would be technically correct from a building physics perspective.
By the way, this is not just a recommendation from the BDF or similar organizations, but a DIN standard requirement, and it applies not only to plastered houses but also equally to brick-clad houses. Many simply do not do it the way that would be technically correct from a building physics perspective.
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