Airtightness patio door / screed

[Jimbouk]

I’ve been going around with an anemometer and have identified a slight draft / air leak coming through the join between the screed / vertical insulation / patio door frame. Just wondering on the best approach to seal this as I don’t want to create a thermal bridge?

 

Will be trimming back the insulation prior to laying engineered oak boards.

 

 

 

 

[Roundtuit]

I'd trim the perimeter insulation, foam any gaps and trim level first, then prime a strip of screed (I used pro clima tescon primer - stickiest liquid I've ever seen!) and carefully seal screed to frame with airtightness tape.  If you've got oak boards going down, you should be able to lap up the frame at least 10mm, which should do the job. Top tip - mark a pencil line to tape to; my free-hand attempts were always regretted.

 

Alternatively, if you can trim the insulation back a few mill below the screed, just fill the gap with a flexible sealant, something like sikaflex ebt.

[Jimbouk]

Thanks, will do!

[gravelld]

On 21/03/2018 at 20:58, Jimbouk said:

I’ve been going around with an anemometer

 

Can you briefly describe your method? I thought this was only used where you have control over where the air movement may occur, e.g. for measuring pressure from ventilation outlets.

Edited April 9, 2018 by gravelld
Doesn't have to be brief!

[Jimbouk]

Nothing sophisticated. I’ve got a testo anemometer, which links to iPad / iPhone. I’ve just prodded the sensor into various parts of the house to see if there is any airflow. In turn found a couple of spots that I think should be draft free that aren’t.

 

At some point I’ll have to learn how to use it properly when I set up the mvhr.

 

Edited April 9, 2018 by Jimbouk

[Gone West]

32 minutes ago, Jimbouk said:

Nothing sophisticated. I’ve got a testo anemometer, which links to iPad / iPhone. I’ve just prodded the sensor into various parts of the house to see if there is any airflow. In turn found a couple of spots that I think should be draft free that aren’t.

 

At some point I’ll have to learn how to use it properly when I set up the mvhr.

 

That's the anemometer I've got and used to set up my MVHR. It's pretty straightforward to use and you can download the results saving having to write them down.

[gravelld]

In the case of a draft doesn't it give very variable results, even as you hold it? Just imagining different wind speeds, moving the stick a few cms by accident...

[Jimbouk]

Well if you wave it around manically or have the shakes yes. I tend to leave the sensor in a location and then look at the iPad, so no localised movement of sensor or air around it. Not very scientific, but is a good indicator so far. 

 

Some of my contractors are convinced that I need to get out more....

[Jimbouk]

I did at one point wonder if the fact that the aluminium frames where probably colder than the internal air temperature and may have been causing an air current themselves, as the warm air rose against them. Hence not an air tightness issue at all.....

 

 

[gravelld]

Use an IR thermometer to check the temperature - I think there's a way of calculating whether a current will occur.

 

IIRC the recco is to have the inner glazing *pane* at 16C so that most won't feel a downdraught in even the coldest external temperatures. However, for a *frame* maybe we can be more lenient because there's much less surface area. That said, it might be the pane contributing to it.

[dpmiller]

That's a nice advert you've got there....