Air gap under roof in attefall house

[Slottsfrun]

There is an air gap between the roof boards and the underlying panels above the insulation in this roof on a newly built attefallshus.

I see that the carpenter has only drilled small holes between the rafters to allow air to circulate in the air gap between the rafters! on the front and back side of the roof. Sloping roof, highest at the front, lowest at the back.

I feel that there might need to be larger openings for air to circulate in the air gap.

Do you have any tips on what I should ask the carpenter to do?

For example, can you use a Fein saw to cut away a certain number of centimeters along the entire length between each rafter? On both sides of the roof.
If so, what is the minimum number of centimeters?

Is there a risk of water getting in then, if it were to rain sideways?

And, what could you attach, and how, to prevent wasps etc. from getting into the air gap?

Or do you have other tips? Would it be enough to just remove a certain stretch between each rafter, i.e., not needing to cut the entire length between each rafter? If possible, maybe it would be easier to find something suitable to place over (smaller area) to prevent wasps from getting in.

I gratefully welcome tips!

Thanks in advance!

 

[Plupp 405730]

We usually have 22mm across the entire width between the rafters, what you need to consider is having insect netting between the rough boarding and the timber paneling😊

 

[Matti_75]

As long as you have air between the insulation and the raw board, it's okay. More air means colder raw board, which in turn can lead to problems.

 

[Slottsfrun]

As long as you have air between the insulation and the roof sheathing, it's okay. More air means colder roof sheathing, which in turn can lead to problems

I think the carpenter has installed some form of board (masonite?) directly above the insulation... and then an air gap between the board and the roof sheathing. Is that done correctly or not?

 

[Slottsfrun]

We usually have 22mm across the entire width between the rafters, what you need to think about is having insect mesh between the tongue and groove boards and the timber cladding😊

Thanks for the input on the matter? Do you have any good tips on a suitable slot vent with insect mesh that would fit in this context? Or can you just staple some form of insect mesh?

 

[Plupp 405730]

Thanks for your input on the matter. Do you have any good tips on a suitable trickle vent with insect mesh that would fit in this context? Or can you just staple some form of insect netting instead?

No, no ready-made solutions; you buy insect mesh on a roll...
It's important to have a little more air than you have now with a few small holes to allow for some air exchange...

 

[Slottsfrun]

No ready-made solutions, instead you buy insect netting on rolls..
It's important to have a bit more air than you have now with a few small holes so there is a bit of air exchange...

OK! How do you attach these most appropriately and with what?

 

[Slottsfrun]

No, no ready-made solutions, instead you buy insect mesh on a roll..
It's important to have a bit more air than you have now with a few small holes for better air exchange...

And, any tips on a good insect mesh on a roll?

 

[Plupp 405730]

And, any tips on a good insect net on a roll?

You staple it to the roof sheathing and then the bottom edge to the facade. You probably need to mount a board to hide the mosquito net otherwise it looks a bit odd.

https://www.hornbach.se/p/insektsnat-protego-20cmx25m/5590488/

 

[Matti_75]

I think the carpenter has installed some form of board (masonite?) directly above the insulation… and then an air gap between the board and the sheathing. Is this right or wrong?

Yes, he has done it completely right.