My house build journey: CLT frame installation (K L trä stomresning), Insulation (Isolering)

The CLT frame was originally scheduled to be assembled on week 50, 2020. It was postponed to week 1, 2021 and again postponed and finally assembled on week 3, 2021.

Nevertheless, this was certainly the most exciting and action packed part of the journey so far. Amazing to see the walls, roof, weatherproofing membranes go up in a span of few days. A lot of good things and some not so good things.

My previous articles at

We needed some preparations to be done before the CLT installation.

It is usually a box like stand that connects to the electricity line that comes up in the site. And later, when walls are done, they build the fasadmätarskåp (Facade meter cabinet) i.e the electricity box with the meter mounted to the outer wall. I went a bit other way with something called as markmätarskåp (Ground meter cabinet).

Markmätarskåp

In this type, a meter is setup on the site and this connection can also be used for construction.

The weather was always going to be a challenge and it made us work even harder. It snowed quite a lot in terms of Skåne standard. The foundation was covered with a thick layer of ice and a lot snow.

It was the day ( Jan 18 ) and I woke up with excitement and got ready to go. Unfortunately on that day there were train problems and 2 back to back trains were cancelled. Wow what an interesting 🤔 start. Finally I had to get a taxi. The one way taxi fare from Malmö to Skurup is the same as monthly train pass 😄

The CLT contractors were waiting on the site. They had began unloading CLT elements on the site. They needed electricity and I had the key to my Groundmeter. As soon I reached, I opened that box and connected their big cables.

The CLT contractors had already visited the site the previous night and sprayed some salt on the foundation so that it would be easier to clean up the thick layer of ice.

Day 1: Unloading CLT elements and outer walls

Unloading CLT elements onto the site
Outer walls assembly
End of Day 1

By end of Day 1, almost all outer walls were assembled. Half of the gable side was assembled

The CLT elements are fixed to the foundation using steel connectors.

There were many screws from 100mm up to 440mm used in different places. The longest were probably in the ridge beam.

Day 2: Inner walls started shaping up.

All inner walls assembled
Upper floor

By end of Day 2, all inner walls were mounted and also the upper floor “floor”. (Mellanbjälklag)

Day 3: Upper floor walls and roof

The roof elements came in another truck of delivery. Some of the elements were directly lifted off the truck and mounted and some of them were unloaded onto the site.

By end of Day 3, the complete CLT shell was done. My SketchUp 3D model literally came alive by the third day

CLT Sketchup Model to Actual CLT on site

The CLT assembly is like giant Lego play but Lego blocks with several thousand kilos assembled by a crane and some sharp skill work. It was just amazing to see how they were working. They are all super skilled and enjoying the whole process as well. Jumping on the roof, getting hold of the elements suspended by the crane, fixing screws, using alignment tools. Mind blown.

Day 4: Insulation studs

I had also given the contract of assembling the insulation studs to the CLT contractors. They usually do build the complete house but only near Gothenburg area. Outside of it, they mostly assembly CLT and sometimes the insulation studs. The insulation studs had come in another delivery on Day 2 itself and unloaded onto other side of house. The insulation studs are I shaped beams. They are also called as I-joists, I-beams. The term lättbalk is used in Swedish.

The roof I joists are 500mm thick and are placed every 1200mm. They support the wood fibre insulation that will be blown in later. One of the benefits of I-joists is lesser thermal bridges. These are also lighter in weight. The alternative is to use wood beams.

The completed roof with I-joists looks like this

I-joists roof insulation studs

I also had hired an another local company to start with the weatherproofing work. They also came in Day 4 and started as soon the roof studs were mounted. First was to mount roof underlay boards(råspont), then exterior insulation boards (I used Steico universal 35mm) and Proclima Solitex 3000 connect and battens are placed every 600mm

This construction pattern is repeated throughout the building envelope. This part of work took quite more time than I expected and on Day 15 (reference from when CLT framing started), it was completed.

Day 18: Roof insulation

Roof Insulation

When mounting the roof underlay boards, the last 2 rows on the top were left open and solitex mento membrane was temporarily fixed. This was opened up again to blow in wood fiber insulation.

Day 19: Wall insulation

For the walls, about 110mm diameter holes were drilled to blow in the insulation and then patched with Tescon Vana tape. The insulation was done in 2 days.

The window and door areas are temporarily covered up with building plastic foils (byggfolie). The winds are so strong that it keeps coming off. The windows have a long waiting time. The roof is set to arrive in about 2 weeks.

On another update, I have managed to find another facade material made of slates (skiffer) which was approved by municipality. This brought down the cost to some extent but all the other unexpected expenses have exceeded the budget quite a lot.

Not so good things

It turned out that the foundation was bad. The foundation is not even and has a dip in the middle up to 25–30mm.

The water standing on the cast foundation was probably a sign. I did ask the foundation contractor and he said it was not a problem but instead good that water is there.

It was disappointing but we couldn’t do much then. I did call the foundation contractor to the site but I did not want to get confrontational during that week. The CLT contractors said they will correct the unevenness for the CLT assembly and used pall bricks(not sure if that is the right word, in Swedish it is called pallbricka to correct the unevenness of the foundation for the time being.

The inspector (Besiktningsman) visited the site the week after the CLT assembly. He spoke to the CLT contractors on the phone and asked for more information about how the pall brick construction was carried out and how the moisture from the foundation will be handled. He did write up a report with the findings. Having the inspector not available when needed has been a big big problem. I wanted to get the cast foundation inspected but he was not available then. Anyways, I have emailed the report to the foundation contractor. Need to take up a conversation and see how it goes.

For the moisture part, the gap between the outer walls have currently been closed up with foam insulation which was one of the solutions suggested by the CLT contractors.

The extra foam needs to be cut out. I am thinking of probably taping it with Tescon vana tape as well. Let’s see.

For the unevenness of the foundation, self levelling concrete (flytspackel) is one of solutions that is commonly used. The question is whether foundation contractor will agree to fix it or not. Will probably know by next week.

A lot of things happened but a lot more to do.

Days left for final inspection: 54 days

Looks impossible. I am yet to contact the municipality to see if they can extend. I don’t even want to think about the fines :(

Solving Problems. Making Software Better. Intrigued by Elegant Solutions. https://twitter.com/agent_hunt

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store