Insulated plasterboard for small front door entrance porch - best way to do this?

veritree

Hello! Another DIY project on the go... 

My front little porch is extremely cold, and I'm convinced there is no insulation. It was built around 20 years ago (I've been told - lived here for 2 years) and last year we had a lot of mould growth because of how cold it got. We also put a curtain across the door to try and block the cold, but this is probably why there was so much mould because there was then no ventilation. 

Anyway, I'd like to insulate this room, and it's too small for any company I've asked to come and inject cavity wall insulation. I'm thinking insulated plasterboard is my best bet. 

My question is more in regards to the ceiling. Will I need to tear the ceiling down, then fill in between the joists with rockwool type insulation, or should I just use insulated plasterboard right over top of the existing plasterboard? I do not have access to the ceiling from inside the house (it has a pitched roof) - and I'm wondering if I can just fully fill the ceiling, or will there be eaves that I need to worry about ventilation? 

I realise I will lose a little floor space around the perimeter, but we are just using it as a coat/storage room/front door. It was 1 degree in there last year!

Also, I'm wondering if I need to add ventilation into this room somehow, to reduce mould growth once insulated? 

 The room is only about 1245mm wide x 1995mm long x 2350mm high

Thanks! 

FFHillbilly

I would definitely remove the old ceiling yes, it will be a much better job with insulation in-between the joists, and you may as well use insulated boards on the ceiling too if you are getting some for the walls.
I'd also have a small tube heater underneath the coats, you can insulate it to death but if theres no heating in there it will be colder than the rest of the house and you'll still get condensation

FreeBear

FFHillbilly said:

I would definitely remove the old ceiling yes, it will be a much better job with insulation in-between the joists, and you may as well use insulated boards on the ceiling too if you are getting some for the walls.

Taking the ceiling down gives you opportunity to mark the walls where the joists are - The amount of waste that it would generate will be small, so easy enough to fill a bin bag or two to take to the local tip.

Certainly put some loft insulation (100mm) up there - I'd put it in at 90° to the joists, and then cut some Celotex type board (same depth as the joists) for a snug fit. 60-75mm thick insulated PB on the walls, and it should be a lot warmer. Ideally, you'd also want to insulate around the door reveal, but there isn't the space there to put anything in.. Even using Aerogel with the thinnest facing board is going to be too thick I fear (as well as being darned expensive).

Tip - Fix the plasterboard to the ceiling first (use screws, not nails), and cut it 50mm (if using 62mm insulated PB on the walls) smaller. remove the top 15mm of PD from the insulated boards so that the ceiling panel overlap is hidden. This will support the edge of the ceiling, reduce any risk of cracks forming, and generally gives a neater finish. When fixing the PB to the walls, expanding foam adhesive will do the job, but do make sure to use mechanical fixings too (Frame fixings with mushroom washers) on ~600mm centres.

Oh, and be careful with your selection of insulated plasterboard - Some use polystyrene (EPS or XPS), others use PIR/PUR foam. The latter is a sometimes a little more expensive, but has a much better thermal performance.

veritree

FFHillbilly said:

I would definitely remove the old ceiling yes, it will be a much better job with insulation in-between the joists, and you may as well use insulated boards on the ceiling too if you are getting some for the walls.
I'd also have a small tube heater underneath the coats, you can insulate it to death but if theres no heating in there it will be colder than the rest of the house and you'll still get condensation

Thank you very much for this! I really appreciate the advice:)

veritree

FreeBear said:

FFHillbilly said:

I would definitely remove the old ceiling yes, it will be a much better job with insulation in-between the joists, and you may as well use insulated boards on the ceiling too if you are getting some for the walls.

Taking the ceiling down gives you opportunity to mark the walls where the joists are - The amount of waste that it would generate will be small, so easy enough to fill a bin bag or two to take to the local tip.

Certainly put some loft insulation (100mm) up there - I'd put it in at 90° to the joists, and then cut some Celotex type board (same depth as the joists) for a snug fit. 60-75mm thick insulated PB on the walls, and it should be a lot warmer. Ideally, you'd also want to insulate around the door reveal, but there isn't the space there to put anything in.. Even using Aerogel with the thinnest facing board is going to be too thick I fear (as well as being darned expensive).

Tip - Fix the plasterboard to the ceiling first (use screws, not nails), and cut it 50mm (if using 62mm insulated PB on the walls) smaller. remove the top 15mm of PD from the insulated boards so that the ceiling panel overlap is hidden. This will support the edge of the ceiling, reduce any risk of cracks forming, and generally gives a neater finish. When fixing the PB to the walls, expanding foam adhesive will do the job, but do make sure to use mechanical fixings too (Frame fixings with mushroom washers) on ~600mm centres.

Oh, and be careful with your selection of insulated plasterboard - Some use polystyrene (EPS or XPS), others use PIR/PUR foam. The latter is a sometimes a little more expensive, but has a much better thermal performance.

Thank you SO MUCH for your advice! This is extremely helpful. Should I fill the ceiling with insulation, or will I need to leave a gap anywhere for ventilation? I suppose I'll know more if there are eaves up there once I pull it down. 

Thank you for the detailed help, I really appreciate it. And yes, I probably won't be able to insulate around the front door and the internal doorway into the rest of the house, but I suppose it'll be much warmer regardless. 

Thanks so much, this is fantastic. 

moneysaver1978

In addition to new insulation, you might want to consider adding some kind of ventilation (especially if you come in from the rain and you put a wet coat or shoes in the room).

veritree

moneysaver1978 said:

In addition to new insulation, you might want to consider adding some kind of ventilation (especially if you come in from the rain and you put a wet coat or shoes in the room).

Yes, that's what I was thinking. Any recommendations? I was curious if it's possible to retrofit trickle vents into the top of the uPVC door, or if there is something else that I should look at? Thanks!

moneysaver1978

veritree said:

moneysaver1978 said:

In addition to new insulation, you might want to consider adding some kind of ventilation (especially if you come in from the rain and you put a wet coat or shoes in the room).

Yes, that's what I was thinking. Any recommendations? I was curious if it's possible to retrofit trickle vents into the top of the uPVC door, or if there is something else that I should look at? Thanks!

Fitting a trickle vent through the PVC door would probably be the easiest and cheapest but according to https://forums.moneysavingexpert.com/discussion/6476764/window-condensation/p1 - it seems to get mixed response.

If I was in your shoes, maybe fit the insulation first and see if condensation/mould continues - if it does then you could look at putting in some kind of ventilation in that little room. Or maybe even a little dehumidifier might suffice (we got one from Amazon for £50 and it seems to be working well).

veritree

moneysaver1978 said:

veritree said:

moneysaver1978 said:

In addition to new insulation, you might want to consider adding some kind of ventilation (especially if you come in from the rain and you put a wet coat or shoes in the room).

Yes, that's what I was thinking. Any recommendations? I was curious if it's possible to retrofit trickle vents into the top of the uPVC door, or if there is something else that I should look at? Thanks!

Fitting a trickle vent through the PVC door would probably be the easiest and cheapest but according to https://forums.moneysavingexpert.com/discussion/6476764/window-condensation/p1 - it seems to get mixed response.

If I was in your shoes, maybe fit the insulation first and see if condensation/mould continues - if it does then you could look at putting in some kind of ventilation in that little room. Or maybe even a little dehumidifier might suffice (we got one from Amazon for £50 and it seems to be working well).

Awesome, thanks so much for the advice!:)

FreeBear

veritree said:

FreeBear said:

FFHillbilly said:

I would definitely remove the old ceiling yes, it will be a much better job with insulation in-between the joists, and you may as well use insulated boards on the ceiling too if you are getting some for the walls.

Taking the ceiling down gives you opportunity to mark the walls where the joists are - The amount of waste that it would generate will be small, so easy enough to fill a bin bag or two to take to the local tip.

Certainly put some loft insulation (100mm) up there - I'd put it in at 90° to the joists, and then cut some Celotex type board (same depth as the joists) for a snug fit. 60-75mm thick insulated PB on the walls, and it should be a lot warmer. Ideally, you'd also want to insulate around the door reveal, but there isn't the space there to put anything in.. Even using Aerogel with the thinnest facing board is going to be too thick I fear (as well as being darned expensive).

Tip - Fix the plasterboard to the ceiling first (use screws, not nails), and cut it 50mm (if using 62mm insulated PB on the walls) smaller. remove the top 15mm of PD from the insulated boards so that the ceiling panel overlap is hidden. This will support the edge of the ceiling, reduce any risk of cracks forming, and generally gives a neater finish. When fixing the PB to the walls, expanding foam adhesive will do the job, but do make sure to use mechanical fixings too (Frame fixings with mushroom washers) on ~600mm centres.

Oh, and be careful with your selection of insulated plasterboard - Some use polystyrene (EPS or XPS), others use PIR/PUR foam. The latter is a sometimes a little more expensive, but has a much better thermal performance.

Thank you SO MUCH for your advice! This is extremely helpful. Should I fill the ceiling with insulation, or will I need to leave a gap anywhere for ventilation? I suppose I'll know more if there are eaves up there once I pull it down. 

Thank you for the detailed help, I really appreciate it. And yes, I probably won't be able to insulate around the front door and the internal doorway into the rest of the house, but I suppose it'll be much warmer regardless.

You don't want to fill the void above the ceiling completely with insulation. You need to look to see how the space is ventilated, and possibly fit some soffit vents on the outside.

Just the external walls need insulating. No point in doing the inner doorway unless you plan to fit an exterior grade door in the opening.

veritree

FreeBear said:

veritree said:

FreeBear said:

FFHillbilly said:

I would definitely remove the old ceiling yes, it will be a much better job with insulation in-between the joists, and you may as well use insulated boards on the ceiling too if you are getting some for the walls.

Taking the ceiling down gives you opportunity to mark the walls where the joists are - The amount of waste that it would generate will be small, so easy enough to fill a bin bag or two to take to the local tip.

Certainly put some loft insulation (100mm) up there - I'd put it in at 90° to the joists, and then cut some Celotex type board (same depth as the joists) for a snug fit. 60-75mm thick insulated PB on the walls, and it should be a lot warmer. Ideally, you'd also want to insulate around the door reveal, but there isn't the space there to put anything in.. Even using Aerogel with the thinnest facing board is going to be too thick I fear (as well as being darned expensive).

Tip - Fix the plasterboard to the ceiling first (use screws, not nails), and cut it 50mm (if using 62mm insulated PB on the walls) smaller. remove the top 15mm of PD from the insulated boards so that the ceiling panel overlap is hidden. This will support the edge of the ceiling, reduce any risk of cracks forming, and generally gives a neater finish. When fixing the PB to the walls, expanding foam adhesive will do the job, but do make sure to use mechanical fixings too (Frame fixings with mushroom washers) on ~600mm centres.

Oh, and be careful with your selection of insulated plasterboard - Some use polystyrene (EPS or XPS), others use PIR/PUR foam. The latter is a sometimes a little more expensive, but has a much better thermal performance.

Thank you SO MUCH for your advice! This is extremely helpful. Should I fill the ceiling with insulation, or will I need to leave a gap anywhere for ventilation? I suppose I'll know more if there are eaves up there once I pull it down. 

Thank you for the detailed help, I really appreciate it. And yes, I probably won't be able to insulate around the front door and the internal doorway into the rest of the house, but I suppose it'll be much warmer regardless.

You don't want to fill the void above the ceiling completely with insulation. You need to look to see how the space is ventilated, and possibly fit some soffit vents on the outside.

Just the external walls need insulating. No point in doing the inner doorway unless you plan to fit an exterior grade door in the opening.

Fantastic, thank you so much! I really, really appreciate the help