Foundations??

[lizzieuk1]

2 minutes ago, Nickfromwales said:

That’s going to be for you to find out tbh. That’s one for lots of googling and ringing and emailing of specs.  
 

Maybe someone on here has bought some like this and can provide a link to the supplier? 

Thanks Nick, its not easy, I've been  trawling for hours hence the post, thought there may be someone on here who's done similar.

[lizzieuk1]

5 minutes ago, Nickfromwales said:

I think for Georgian style the glazed units just come pre fitted with the bars?

Found these and I think the may do 3g so will enquire. 

[Nickfromwales]

12 minutes ago, lizzieuk1 said:

Thanks Nick, its not easy, I've been  trawling for hours hence the post, thought there may be someone on here who's done similar.

Maybe start a new thread in the doors and windows forum to wake the gods, vs hoping someone finds this in the foundations thread 👌. Prob get more responses that way, specific to the windows 👍👍

[Iceverge]

OK here are some numbers for our 185m2 house after having a play with PHPP.

 

Out annual heat demand is 2625kWh. Passiv windows with 3G , 200mm EPS in the floor (u = 0.16) , 250mm EPS bonded beads in the walls (0.15) , 400mm Cellulose in the attic. (0.1)  Airtightness 0.31 ACH50. 

 

 

Here are some Airtightness figures. 

 

• 0.31 ACH = 2625kWh
• 1 ACH = 3012kWh
• 2 ACH= 3586kWh
• 3 ACH= 4170kWh
• 4 ACH= 4716kWh
• 5 ACH= 5537 kWh
• 6 ACH= 5861kWh

 

Now I play the same game but step back the other fabric of the house individually to say a bregs basic house of a few years back. 

 

• Floor U 0.3 = 3103kWh
• Wall U 0.235 = 4005kWh
• Roof U 0.175 = 3159kWh
• Double Glazing = 3387kWh
• Lose MVHR = 5365 kWh

 

Keep the airtightness and MVHR but use the poorer figures everywhere else

• 5918kWh

 

MVHR and  airtightness are the biggest wins. 

 

 

Then come glazing and U value. This isn't as straightforward to generalise as window areas vary, a bungalow will have much more wall than a 3 story town house. Insulation has to be improved all together really. Not much point in adding 50mm to the attic insulation when its already at 500mm. It only reduced the U value by 0.008W/m2K. However if you add 50mm to 100mm wall insulation it takes it from 0.4 to 0.26. 16 times more of a difference. 

 

I concluded in our house for the above insulation types the ratio of increasing the insulation in the following ratio was the most economical. YMMV depending on construction specifics. 

• 4 Floor
• 5 Walls
• 8 Roof

Hope this helps. 

 

 

[Iceverge]

As an aside 3G, Airtightness and MVHR were always going to be included for the comfort, noise, air quality and building health aspects. 

 

Payback was considered but it wasn't really ever up for discussion given the other benefits.  

[JohnMo]

10 hours ago, Iceverge said:

Out annual heat demand is 2625kWh. Passiv windows with 3G , 200mm EPS in the floor (u = 0.16) , 250mm EPS bonded beads in the walls (0.15) , 400mm Cellulose in the attic. (0.1)  Airtightness 0.31 ACH50

Shows how much difference form factor makes as well, we are long thin single storey with all vaulted ceilings. Again MVHR, 3G passive spec windows (but quite a lot of them)

 

Our U values

Floor 0.09

Roof 0.12

Walls 0.14

 

Our heating usage is near double yours.

[Iceverge]

Our actual measured heat usage was a bit more, 3.2MWh/annum. Not sure of why the difference to PHPP. 

 

The insulated envelope of our house is essentially a 8.5mx13.5mx5.5m box so a good form factor like you say. We're quite a distance further south than you too.

 

What was your blower door result and window spec?

 

 

 

 

 

 

 

[JohnMo]

16 hours ago, Iceverge said:

The insulated envelope of our house is essentially a 8.5mx13.5mx5.5m box

 

70m perimeter, approx 8x25m and average of 3m tall except lounge which is 6m tall.

 

16 hours ago, Iceverge said:

What was your blower door result and window spec?

Average window U_w 0.6, our glass doors came double glazed (krypton filled) and are 1.2, front door 1.0.

 

We had a blower test prior to plasterboard at 2, fixed all the leak areas (mostly at DPC), but at final test it still came in a 2. But the MVHR wasn't sealed very well during test. So suspect better than 2 by a decent margin, could feel a definite breeze where the MVHR units are located. Couldn't be bothered doing a further test.