ᐅ Experiences with "Thermisto Swift" / Underfloor Heating for Retrofitting by Cutting Grooves

Hello,

has anyone here had experience with Termisto Swift?
It involves floor heating channels milled into the screed after installation.
Thermisto apparently inspects the screed beforehand and provides a warranty on durability and load capacity.
We are considering this Thermisto system for our renovation of an older building.

Thanks in advance.

Best regards,
Thomas

chippy79 schrieb:

Sorry for bringing up this topic again, but we actually have the same question in our project. Are there any experiences so far? Thanks.

I have looked into the topic but will now install a traditional underfloor heating system. Milling is really expensive, so I prefer to "simply" have the screed broken out and install a low-profile underfloor heating system (in my case 20mm (0.8 inches) PUR insulation with a thermal conductivity rating of WLG 22/23, foil with grid, 16mm (0.6 inches) pipes stapled in place, 45mm (1.8 inches) F5 anhydrite flow screed). The price is basically the same.

Yes, I also initially thought it would be more expensive. But I received a quote from a company where, including materials and milling, it actually comes out significantly cheaper. After all, you also save on removing and disposing of the old screed.

For me, it’s currently about 14,000 EUR for the new heated screed option,
including screed removal 3,000 EUR,
screed disposal 1,000 EUR,
materials and installation of underfloor heating 6,000 EUR,
materials and installation of screed 4,000 EUR.

And only about 7,000 EUR for the milling-in option.

What I’m wondering is how do you determine the quality of the floor insulation (in our case on the first floor) then?

chippy79 schrieb:

What I’m wondering is, how do you know how well the floor insulation (in our case on the first floor) performs?

Completely unchanged compared to the previous insulation. If in doubt, you’re also heating downward. But €10,000 sounds like a lot. What’s included?

nordanney schrieb:

Completely unchanged from the previous insulation. If in doubt, you are heating downwards as well. But €10,000 sounds like a lot. What does that include?

Yes, sorry, I revised it above afterward and itemized the costs. I even had more expensive quotes just for installing the underfloor heating, around 8000 EUR for 110 sqm (1184 sq ft). That only included the insulation, installation system, pipes, manifold, etc., but not the removal, disposal, and installation of the new screed.

Oh, and one more note. It’s on the first floor (1st floor / upstairs), so it might not be as "bad" if you end up heating downwards as well?

The company offering the groove-cutting method will do an on-site inspection if hired, meaning they will do some test drillings. Maybe then they can also determine how much insulation is currently installed?
My thought was also that when removing the screed, I wouldn’t know what’s underneath, and disposal might be very expensive if it’s screed with insulation material. This way, I could save those costs and time.

chippy79 schrieb:

Yes, sorry, I made some additional edits above and broke down the costs.

chippy79 schrieb:

For me, it’s currently about €14,000 for the new heated screed option,
including removal of screed €3,000,
disposal of screed €1,000,
material and installation of underfloor heating €6,000,
material and installation of screed €4,000.

Steep price!
For me:
Removing and disposing of 120 sqm (1,292 sq ft) of screed costs about €3,000 (knocking off parquet and tiles, removing and disposing of screed. Also gutting two bathrooms, demolishing one wall. There was a parquet floor and lots of tiles covered in the pantry. I took old polystyrene insulation from 1967 to the recycling center free of charge).
Material and installation of underfloor heating (I mentioned the construction layers above) cost about €2,500 for materials and €1,000 for installation.
Material and installation of screed about €2,500 total.
All invoiced. Total around €9,000 (but more work than you). The gutting is already done; the other work is ordered. Specifically, for screed at 45 mm (1.8 inches), I was quoted between €18 and €22 per sqm (plus tax) by various screed layers.

That’s why I asked about the details of your quote.

chippy79 schrieb:

Oh, and one more note. This is the first floor, so maybe it’s not so “bad” if you additionally heat downwards?

Yep.