Trusteel mk2 or 3m?

[Cornishman07]

Hi,
We live in a trusteel steel frame house built in 1966. We're building an extension in September and completely renovating the existing house at the same time. I
I would like to research into what insulation options we have for the walls/floor but don't know what type of steel frame it is! I gather there's an earlier MK2 and later 3m but after searching the web the same pictures and descriptions come up for both 3m and MK2! How are they different and how can you tell which is which? I have enclosed a picture of the roof trusses to help identify my house type! The frames are made up of 4 angles with lattices riveted into 6” deep, 2 3/8" wide sections and spaced at 2'9” centres which matches a description of 3m I've found but I've seen similar pictures labelled mk 2!





Many thanks
Richard

 

[^woody^]

The lattice frame indicates it's a Mk2. 3M used 'C' sections

 

[Cornishman07]

Thanks for the reply woody.
I got the info off bisf/non standard house but was confused because there was a technical description of 3m but no pictures, and pictures of MK2 but no technical description!
3m description;

MK2 pictures;

I then found this post with a picture that exactly matches my house but someone replied it was "100% trusteel 3m"

Apologies for the long post, I didn't realise it was such a minefield! I guess from an insulating point of view the type of frame is irrelevant, the same rules would apply to either type?

 

[noseall]

3M used 'C' sections

Smaller hips on the 3M's?

 

[^woody^]

Thanks for the reply woody.
I got the info off bisf/non standard house but was confused because there was a technical description of 3m but no pictures, and pictures of MK2 but no technical description!
3m description;
View attachment 195915
MK2 pictures;
View attachment 195916 View attachment 195917
I then found this post with a picture that exactly matches my house but someone replied it was "100% trusteel 3m"
View attachment 195918
Apologies for the long post, I didn't realise it was such a minefield! I guess from an insulating point of view the type of frame is irrelevant, the same rules would apply to either type?

Where is that post from?

It's not a minefield. BRE has reported on these properties, and its clear regarding the steel section types for each property. 3M was introduced in 1966, but there was a period when both types were in construction before the Mk2 was discontinued.

I'll have a look if there is anything else to be aware of regarding insulation, but as one of the main defects is corrosion of the stantion bases, that could influence how walls are insulated.

 

[Cornishman07]

Ha yes, minefield is a bit of an exaggeration!
I just meant I didn't find it as straightforward as I thought to get a difinitive answer, and when I thought I had, it turns out it was wrong! And I've still not found a picture of a 3m frame. Will have a look on BRE.
All Those screenshots i posted were from the bisfhouse website whilst the last screenshot was a reply from one of the admins in a 'what type of house' forum also on bisfhouse.

The extension is going on the gable end and it's a semi so only the front and rear walls need insulating and even then most of the area is taken up with windows, which are also being replaced! I was thinking of taking off the current internal boards (they're a bit like giant sheets of wheetabix) and replacing with 18mm exterior ply, then a 62.5 mm insulated plasterboard over, so nothing actually in the cavity