insulated slabs

have2flushtwice

hi all
for insulated slabs inside the house on a new build, how much is enough?
I know there is 52.5, and 70mm. but what are the insulation values of these, when using a 150mm cavity?

my options:

150mm cavity and 52.5 slab.

increase the cavity to 200mm and use a 52.5.

200mm cavity and 70mm slab?

fyi:
north side of the house will be triple glazed and south will be double. 100mm under floor insulated slab.

I'm not aiming for air tightness, and the heat system will be air to heat.
thanks.

Gumbo

have2flushtwice wrote: »

hi all
for insulated slabs inside the house on a new build, how much is enough?
I know there is 52.5, and 70mm. but what are the insulation values of these, when using a 150mm cavity?

my options:

150mm cavity and 52.5 slab.

increase the cavity to 200mm and use a 52.5.

200mm cavity and 70mm slab?

fyi:
north side of the house will be triple glazed and south will be double. 100mm under floor insulated slab.

I'm not aiming for air tightness, and the heat system will be air to heat.
thanks.

Nobody can answer that without the DEAP / BER details. 82mm might be sufficient on one house but the next could need 100mm depending on layout, volume etc

What does your preliminary BER assessment stipulate?

893bet

What is the point of all the insulation if you are not doing Airtightness?

Why have loads of insulation and then leave a window open. Like wearing a nice wool cardigan but leaving the zip of it open so the cold gets in and your heat gets out!

893bet

What is the point of all the insulation if you are not doing Airtightness?

Why have loads of insulation and then leave a window open. Like wearing a nice wool cardigan but leaving the zip of it open so the cold gets in and your heat gets out!

have2flushtwice

I don't want an airtight house - I want a warm house. Is there a need to go to the added expense of air tight certification?

BryanF

have2flushtwice wrote: »

hi all
for insulated slabs inside the house on a new build, how much is enough?
I know there is 52.5, and 70mm. but what are the insulation values of these, when using a 150mm cavity?

my options:

150mm cavity and 52.5 slab.

increase the cavity to 200mm and use a 52.5.

200mm cavity and 70mm slab?

fyi:
north side of the house will be triple glazed and south will be double. 100mm under floor insulated slab.

I'm not aiming for air tightness, and the heat system will be air to heat.
thanks.

1. Keep all insulation in the one location - ie in the cavity
2. Go with good windows on all sides, double on south is nonsense
3. 150 PIR min under floor
4. Educate your self as regards air-tightness

Welcome to the c&p forum

MicktheMan

have2flushtwice wrote: »

I don't want an airtight house - I want a warm house.

Classic!

have2flushtwice

All very helpful I see.

lownhard

have2flushtwice wrote: »

I don't want an airtight house - I want a warm house. Is there a need to go to the added expense of air tight certification?

An airtight house is a warm house! Draughts and gaps in the airtightness layer are what make a house feel cold and cause heat loss in a house.

If you want a warm house you need to strike a cost effective balance between airtightness and insulation. Probably 150mm PIR in the floor, 200mm fully pumped cavity and 400-600mm of high performance wool or cellulose in the roof, couple with clever airtightness strategy designed by a suitably qualified professional.

Why spend thousands on high levels insulation that will be rendered ineffectual by cold draughts coming into the house?

Arguably airtightness is the most important contributor to a warm house.

You are at the beginning of your learning. Study the concept of a passiv haus / passive house and apply the principles as far as the budget will allow, and you wont go too far wrong.

Start here and watch all the videos about the denby dale house that are in the series.

have2flushtwice

Thank you lownhard

lownhard wrote: »

An airtight house is a warm house! Draughts and gaps in the airtightness layer are what make a house feel cold and cause heat loss in a house.

If you want a warm house you need to strike a cost effective balance between airtightness and insulation. Probably 150mm PIR in the floor, 200mm fully pumped cavity and 400-600mm of high performance wool or cellulose in the roof, couple with clever airtightness strategy designed by a suitably qualified professional.

Why spend thousands on high levels insulation that will be rendered ineffectual by cold draughts coming into the house?

Arguably airtightness is the most important contributor to a warm house.

You are at the beginning of your learning. Study the concept of a passiv haus / passive house and apply the principles as far as the budget will allow, and you wont go too far wrong.

Start here and watch all the videos about the denby dale house that are in the series.

JonathonS

You will pick up a few pointers on the Wexford Passive House FB blog.

https://www.facebook.com/Passive.House.Wexford/photos/a.163708813834231.1073741828.154344008104045/163708943834218/?type=3&theater

hexosan

have2flushtwice wrote: »

I don't want an airtight house - I want a warm house.

:eek::eek::eek: priceless