ᐅ Railings on ETICS – What Solutions Are Available?

Hello everyone,

I have a 100m² (1,076 sq ft) roof terrace with an EPDM flat roof membrane, and Douglas fir boards laid on top in a floating manner.
Now, I want to install a railing, but I don’t want to simply screw it directly onto the Douglas fir boards. At least, that doesn’t sound very stable to me.
What options are there for attaching a railing to the outside of the house when the exterior wall consists of a 10cm (4 inch) thick cross-laminated timber (CLT) panel with 20cm (8 inch) of wood fiber insulation on the outside?

Did I understand correctly that some kind of sleeves are needed to create a form-fit connection between the CLT wall and the railing posts?

Regards,
Tito

titoz schrieb:

Hello everyone,

I have a 100m² (1076 sq ft) roof terrace with an EPDM flat roof membrane, and on top of that, Douglas fir boards are installed as a floating deck.
Now, of course, I want to have a railing, but I don’t want to just screw it directly onto the Douglas fir boards. That doesn’t sound very stable to me.
What options are there for attaching a railing on the exterior of the house if the exterior wall is a 10cm (4 inch) thick cross-laminated timber panel with 20cm (8 inch) wood fiber insulation?

Did I understand correctly that some kind of sleeves are needed to create a positive connection between the cross-laminated timber wall and the railing post?

Regards,
Tito

I suppose that based on your description, you don’t just want a railing, but you will probably need one for fall protection. There are likely relevant standards or codes for attachment methods, but how about fixing the railing as you suggested, directly on the terrace surface? A good approach would be to have a wider, solid edge beam (a thick larch wood board worked well for me) either on or better yet beneath the decking boards. I had to do this myself due to lack of other options, and if the terrace area is not too large (oh, reading again: 100m² (1076 sq ft)... :-( ), the corner-mounted railings might provide enough stiffening—possibly with additional angled supports braced inward into the terrace. A photo could really help many to better assess the situation and offer advice beyond my suggestion. 😎

I would avoid perforating the external thermal insulation composite system (ETICS / external wall insulation) too often, but at least check with the installer beforehand. A well-installed ETICS stays intact, and there are always appropriate (though often costly) solutions for such fixings.

And hopefully, you didn’t just turn a flat roof (which was “there” before) into a terrace without considering any resulting setback requirements?

Regarding your ETICS again. We have a similar wall structure, and one thing you absolutely must avoid is letting air (moisture) from outside penetrate the wood fiber insulation. Surface water is one issue, but the load on the railing will cause the weather-resistant layer (render?) to crack and become leaky. Moisture will enter along the thermal anchors or similar fasteners, and you can watch your wall deteriorate over time. For me, the risk is too high. The topic of the facade (airtightness / connections / fastenings, etc.) was discussed almost daily for some time in our case—among others, during breakfast with my brother’s son-in-law, who is the master carpenter for the construction company that built and assembled our house.

@superzapp :
Thank you for your response.
Something similar to the edge strip you described had already crossed my mind.
I just have concerns that the wood might rot over time, which could compromise the overall stability.
Do you have a picture of your solution?

Use the Fischer Thermax system for the railing. Be careful. The adhesive mortar needs to be applied cleanly and in sufficient quantity.

@superzapp :
My builder told me back then to simply screw a thick beam all around onto the boards and then build my railing out of wood on top of that.
I was always concerned that the wood would start to rot if wood is screwed onto wood and there is regular moisture.
Of course, that would be the easiest option for me since I enjoy working creatively with wood myself.