Live self-Builds - mod warning in post no. 1

Villain

893bet wrote: »

Electritions are flying! Really happy with how neat they are!

Don't skimp on Cat5 or even Cat6, even if you don't intend on using them now, coax should only be for satellite and aerial.

Superdaddy

893bet wrote: »

Slow work!!

I am about to start this now. I took on the air tightness and insulating between rafters and floors myself. I saw some of the work the contractors were doing and I wasn't filled with confidence.

I have been considering scratch coating around the windows first then taping them and then skim coat. Is there a reason it shouldn't be done that way?

Just need to finish stuffing super glass insulation between the rafters, absolute torture in this heat.

hexosan

Tape sticks better to the block before it's scratched

fclauson

pictures of taping at https://www.facebook.com/Passive.House.Wexford

893bet

Slow !

893bet

Its not to bad. If anyone is thinking about doingn themselves but not sure I'd say give it a go if you have plenty of time on your hands.

just do it

893bet wrote: »

Its not to bad. If anyone is thinking about doingn themselves but not sure I'd say give it a go if you have plenty of time on your hands.

Good on you, I look forward to the results of your airtightness tests

893bet

just do it wrote: »

Good on you, I look forward to the results of your airtightness tests

I dread them lol!

hexosan

3 days into doing my windows. One thing you definitely need is time.

just do it

Well lads I'm of the opinion you ye can do it I can do it . I hope to be at this stage within 6 months... fingers crossed....

893bet

3 men, 2 days, 130 slabs! Done!

893bet

Expanding metal over roof membrane before sand and cement!

BarneyMc

893bet wrote: »

Expanding metal over roof membrane before sand and cement!

Is the expanded metal used instead of taping it to the wall?

893bet

BarneyMc wrote: »

Is the expanded metal used instead of taping it to the wall?

At this junction tape is not typically used. A type of mastic glue is what I used as directed by seller. Stuff comes in silicone type tubes. 100 mm of membrane is left hang down along each wall and a bead of the mastic put along this and the tape pressed against the wall to seal. You need the expanded metal then in order to cover it with the sand and cement as it wouldn't take to the membrane otherwise.

hexosan

Can't see why the mastic is needed if the membrane is plastered over, that in itself should create your airtight seal.

How is it any different to wrapping the slabs, meshing the membrane and plastering over. ??

893bet

hexosan wrote: »

Can't see why the mastic is needed if the membrane is plastered over, that in itself should create your airtight seal.

How is it any different to wrapping the slabs, meshing the membrane and plastering over. ??

I agree with you but that is what is recommended!

hexosan

Any chance the fella suggesting it was also sell the mastic

893bet

hexosan wrote: »

Any chance the fella suggesting it was also sell the mastic

He does but that is what the manufacturer recommends. That's how it is done. There is little point spending well over a grand on membranes and tapes if you are going to cheap out and not spend the 100 quid on the mastic for the final step.

just do it

893bet wrote: »

He does but that is what the manufacturer recommends. That's how it is done. There is little point spending well over a grand on membranes and tapes if you are going to cheap out and not spend the 100 quid on the mastic for the final step.

Maybe hexosan is right but I'd be with you on doing it. Maybe you could get away without it but do you really want to take the risk? The builder kept telling me the engineer had overspec'd the house but I don't want to ever have even the slightest fleeting thought that maybe I shouldn't have taken a particular builder's shortcut.

stickybookmark

hello, joining in. Foundations poured yesterday. 310m2 two storey house in Cork. Will be busy now for the next 12 months.

just do it

stickybookmark wrote: »

hello, joining in. Foundations poured yesterday. 310m2 two storey house in Cork. Will be busy now for the next 12 months.

Best of luck with the build. What's the detail? Foundation, walls, windows etc

893bet

Plastering upstairs completed!

stickybookmark

just do it wrote: »

Best of luck with the build. What's the detail? Foundation, walls, windows etc

Thanks. Strip foundations. Block walls through the whole house. Concrete slab 1st floor. Geothermal heat pump. Underfloor heating throughout the whole house. Heat recovery ventilation (looks like I'll need 2 units coz of the size of my house apparently 300m2 is the cut off point) Haven't decided on windows.
Only really looking at a lot of things now like bathrooms, kitchen, windows, doors, skirting & architrave, lights etc. what stage are you at yourself?

just do it

stickybookmark wrote: »

Thanks. Strip foundations. Block walls through the whole house. Concrete slab 1st floor. Geothermal heat pump. Underfloor heating throughout the whole house. Heat recovery ventilation (looks like I'll need 2 units coz of the size of my house apparently 300m2 is the cut off point) Haven't decided on windows.
Only really looking at a lot of things now like bathrooms, kitchen, windows, doors, skirting & architrave, lights etc. what stage are you at yourself?

What size cavity? What levels of insulation in the floor and roof and U-values of doors and windows? What about cold bridges and your airtightness target?

I'm on a sabbatical from the build at the moment. First floor is in. I'm going certified passive with a 250 mm cavity, quin lite first coarse of blocks and airtightness membrane wrapped around concrete first floor. This thread had been very quiet so you wouldn't have to go back much to find pics

fclauson

stickybookmark wrote: »

... Heat recovery ventilation (looks like I'll need 2 units coz of the size of my house apparently 300m2 is the cut off point) ...

Word of warning - we put in 2 HRVs for this reason but there can be some very odd effects
1) the balancing of the two can be difficult where you need more extraction in one end of the house to the other (ours is a bungalow) hence one unit is doing more extraction than inputting while the other is doing more inputting than extraction

2) our house is a broken L shape - and if the wind is from one direction you can get a cross flow across the house due to pressure on the external surfaces - now this is not a draft but it does make a candle flame held at the gap in the doors in the middle of the house when they are closed to just bend slightly in the direction of the cross flow. Its not an issue in reality - the way to fix this would be to have all the ducts coming out on the same external wall (suitable separated so you are not sucking in air you just expelled)

happy to provide more info if needed

just do it

fclauson wrote: »

Word of warning - we put in 2 HRVs for this reason but there can be some very odd effects
1) the balancing of the two can be difficult where you need more extraction in one end of the house to the other (ours is a bungalow) hence one unit is doing more extraction than inputting while the other is doing more inputting than extraction

2) our house is a broken L shape - and if the wind is from one direction you can get a cross flow across the house due to pressure on the external surfaces - now this is not a draft but it does make a candle flame held at the gap in the doors in the middle of the house when they are closed to just bend slightly in the direction of the cross flow. Its not an issue in reality - the way to fix this would be to have all the ducts coming out on the same external wall (suitable separated so you are not sucking in air you just expelled)

happy to provide more info if needed

You're a perfectionist fc, would the average mere mortal notice?
(meant in humour, doesn't always come across that way in the written word )

hexosan

Beam have MVHR unit options that can service a house that size from a single unit. The Heru 130 & 180 plus they have a passive certified unit but can't think of the model name now.

fclauson

All I would say is do the maths and installed nothing without being confident the installer knows what he is talking about - units with no ducts connected have a certain air flow but once you start adding the back pressure of duct work etc their performance will drop.

Remember you need to service the boost/max airflows as well as normal ventilation
Ensure the unit is not running at or near max all the time as this typically will be more noisy

893bet

Starting to come together.

Hoping to start elextrical second fix next week and plumbing second fix to follow!

Jalopy81

Hi All.
New to posting on boards but have been lurking around this forum for a few years particularly about airtightness. Just got test done and come back at 1.3 ach on a block built house.
Just thought I'd return some of the knowledge gained here. I have taken loads of photos during construction so if I can help anybody during the long hours of origami folding tapes and membranes just let me know