Ms Catherine Weitbrecht

[Iceverge]

This has me baffled a bit. 

 

I'd really like to see a picture of the first floor slab under construction. 

 

Were the perimeter blocks definitely included as per the porotherm spec when this was done? Are you sure it was a porotherm floor and not a hollow core slab? 

 

I had thought all the moisture had originated from inside but I'm not certain now. Some of this looks like driven rain. Am I correct in thinking you are very near the sea from one of the pictures? 

 

As @Mr Punter noted Porotherm is maybe not the most suitable product in such a wet environment but rest assured you're not alone. Lots of other types of solid walled buildings are facing similar issues. I also know of one EWI house and several ICF houses near me that have had issues with the render cracking and falling off. 

 

More broadly I think that we need a EWI retrofit option that includes a cavity as this is really important for durable retrofit. 

 

Here's a image from Knauf Rocksilk with a standoff cement board. 

 

 

Beeatie Passive did a retrofit with a void created by fiberglass brackets and cement board that was pumped with EPS beads. 

 

 

 

 

Both would be excellent options for your house @Catherine Weitbrecht

 

They would lightly be expensive however and unusual options domestically.

 

 

 

 

 

 

 

 

[Catherine Weitbrecht]

  Thank you again for your continued efforts to try and get more clarity on the issue.

 

The closest thing I can give you to a picture of the slab is this website, scroll down to pictures  12/13/ 14/15.   This is the general concept of the ceiling.

I do not know how far they followed this exactly when they built it. 

 https://beodom.com/en/news/entries/making-of-amadeos-first-floor-slab-with-precast-beams-and-ceiling-bricks.html

 

It is definitely a proton construction ceiling

We live about 4 miles from the sea as the crow flies. 

Regarding the EWI as a proposed solution I am a little nervous of the process ie the drilling into the existing structure ie the protherm blocks ( they are a  honeycomb structure and any drilling could facilitate more access should any water get in.. 

How weather and water proof is EWI as a concept and I wonder ultimately how compatible it would be with the proton blocks? 

 

 

On another matter - I forgot to include a picture of a section of the lower wall ie near the skirting - It seems to be worse under window  and where holes were drilled in the proton walls to accommodate piping for the central heating system.  

I do have a local builder/ plaster coming to have a look on Sunday, he specialised in Lime building. Perhaps a fresh set of eyes my uncover something. Fingers crossed

Sincerly Catherine 

ps 

My brother made this comment about the construction process at the slab section of the wall.  

 

""Going back to construction methodology. Every mechanical joint is a potential problem, the proton system minimizes this with their hopper/tray system of applying a thin layer of mortar before the next course of blocks is laid.

-Slab construction.

I would imagine that the course of half blocks (in width) to accommodate the concrete joists/slab was laid 1st.

Then the concrete joists,

Then the infill blocks between joists,

The concrete slab.

The screening/levelling of the concrete was more than likely done from the top of the 'half block'.

 

This would imply that the half block was laid to the same standard and was a 'good joint', less any potential subsequent slab movement.

 

The Q is how would they start off the next course of proton blocks after the slab, the hopper/tray system wouldn't work as the new base is half proton block /half concrete slab, was the mortar trowelled on instead? is this potentially the worst mechanical joint in the entire house?

 

 

[Catherine Weitbrecht]

Just wondering if you have had any more thought bases on my reply ? 

[Iceverge]

Sorry @Catherine Weitbrecht didn't see this. 

 

Perhaps use the @ symbol to tag me in the posts so I'll get a notification. 

 

I'll have a look tomorrow. 

[Iceverge]

On 21/02/2024 at 22:26, Catherine Weitbrecht said:

The closest thing I can give you to a picture of the slab is this website, scroll down to pictures  12/13/ 14/15.   This is the general concept of the ceiling.

I do not know how far they followed this exactly when they built it. 

 https://beodom.com/en/news/entries/making-of-amadeos-first-floor-slab-with-precast-beams-and-ceiling-bricks.html

 

Hi Catherine I saw that but I wasn't sure if they had done exactly the same detail on yours. 

 

On 21/02/2024 at 22:26, Catherine Weitbrecht said:

do have a local builder/ plaster coming to have a look on Sunday, he specialised in Lime building. Perhaps a fresh set of eyes my uncover

 

Did he have any further information to add?

 

On 21/02/2024 at 22:26, Catherine Weitbrecht said:

Regarding the EWI as a proposed solution I am a little nervous of the process ie the drilling into the existing structure ie the protherm blocks ( they are a  honeycomb structure and any drilling could facilitate more access should any water get in.. 

How weather and water proof is EWI as a concept and I wonder ultimately how compatible it would be with the proton blocks? 

 

 Normal EWI relies on a face of impermeable acrylic or silicone render to stop the moisture so the holes in the Porotherm wouldn't really matter 

 

However.....

 

Being so close to the sea I am inclined to suggest something with a cavity is a better plan. EG an airspace behind the externally cladding. 

 

Maybe battens and fiber cement siding. 

 

Have you done anything to tackle the ventilation of the house? 

 

 

[Catherine Weitbrecht]

@IcevergeThanks so much iceverge.

I am delighted you have not given up on me! 

 

The said builder has not arrived yet!

Yes much to consider re EWI

 Re the ventilation, as the outside and inner plaster are both lime-based, we were under the impression that condensation would not be such a problem as the walls themselves can regulate a certain amount of water vapor. I have found a spare bag of what the house was plastered with Knauf MP 75  and MPL 

MFL  20 KG   https://www.stewes.de/quick-mix-MFL-Faser-Leichtputz-20-kg/p/30050681

Knauf MP 75  https://knauf.com/api/download-center/v1/assets/9f6c1a83-c97c-480c-b7b7-31d3bcd30d60?download=true

Another question that I prefer not to ask here so can you email me at ctweitbrecht@gmail.com ? 

Thanks again

 

 

[Iceverge]

10 hours ago, Catherine Weitbrecht said:

@IcevergeThanks so much iceverge.

I am delighted you have not given up on me! 

 

The said builder has not arrived yet!

Yes much to consider re EWI

 Re the ventilation, as the outside and inner plaster are both lime-based, we were under the impression that condensation would not be such a problem as the walls themselves can regulate a certain amount of water vapor. I have found a spare bag of what the house was plastered with Knauf MP 75  and MPL 

MFL  20 KG   https://www.stewes.de/quick-mix-MFL-Faser-Leichtputz-20-kg/p/30050681

Knauf MP 75  https://knauf.com/api/download-center/v1/assets/9f6c1a83-c97c-480c-b7b7-31d3bcd30d60?download=true

Another question that I prefer not to ask here so can you email me at ctweitbrecht@gmail.com ? 

Thanks again

 

 

 

Of course not, I'm interested in seeing a conclusion as I don't think you situation is isolated. 

 

Ventilation and "breathability" are often confused. In fact breathable is a bit of a pointless term in itself I think. Everything is breathable really. It's a measure basically how small the microscopic holes in a material are. At some rate there's a particle small enough to get through every material. 

 

Better to think of things as a level of "vapour permeability" this can be measured in SI units. ,Mega (or Giga )Newton seconds per gram metre. All a bit abstract for building, but the point remains. 

 

If something is very vapour permeabile like mineral wool it won't trap moisture. Something like Aluminium foil will. 

 

Lime render is so where in the middle.

 

However It will do absolutely zero for your Ventilation. 

 

This is the air you need to breath in your lungs, and take away moisture in the air and bad gases.

 

This requires a continuously running fan to have any consistent results. All the lime plaster in the world won't help. 

 

As a rule I think it's better to keep things public ,if you can, for peer scrutiny and support but if you need to message me there's a little envelope symbol in the top corner of your screen for a PM (personal message)

 

 

 

 

Edited March 8 by Iceverge