Airtightness - Floor to wall

rampantbunny

I'm looking at the floor to wall junction at the moment for airtightness.
I have a tape which is used for this junction but I'm not 100% how/where to fix it.
Provisionally, it will be glued to the plastered wall and screed, but that leaves it exposed to damage...especially when skirting board is fitted.

I'm looking for different methods of sealing this junction.
e.g. glue to wall first and then plaster over?
embed in the screed somehow, or glue on top?

If anyone has any pictures they'd be welcome.

ht9zni1gs28crp

The floor to wall tape needs to be under the screed and glued/taped to wall to enable plaster(airtight line) to extend over it. The tape used here is a wide format up to 200mm and is more an EPDM style membrane than your usual Airtight membrane.

rampantbunny

miller_63 wrote: »

The floor to wall tape needs to be under the screed and glued/taped to wall to enable plaster(airtight line) to extend over it. The tape used here is a wide format up to 200mm and is more an EPDM style membrane than your usual Airtight membrane.

I've the same tape.

Air ingress is probable if beneath the DPC line there is un-plastered rising blockwork.
I'm considering applying that tape, from above the DPC to below, by either gluing or plastering into the wall.

For your detail to be airtight, wouldn't the screed have to bond to the tape as it is poured onto/sits on it?
Did you install a layer of polythene over the insulation which I think is customary? If you did, how would the screed form this airtight bond?

Plastering the tape to the wall is not much different to gluing it on with the proper mastic.
It offers only minimal additional protection. If a carpenter screws/nails skirting to the wall, the tape is punctured with either approach.

Sorry, not trying to pick holes in your approach. I think there is more than one way to skin the proverbial.

ht9zni1gs28crp

The tape is well over the DPM line. This is glued to the wall and to the insulation slab taking care to leave a movement crease in the tape itself.

Why would the screed need to 'bond' to the membrane any more than what it does once its sat and cured over it? The screed is airtight itself on the same lines as your plaster line.

Fair enough in each to their own detail, I responded with how it worked for us. I guess your trying to achieve Passive Standard ACH or lower if your concerned about carpenter nails into wall for skirting board for air ingress?

delfagio

I know I'm a SIP timber frame house but What I done is used an airtight tape to tape the bottom of the timber frame to the subfloor. I had to use a primer glue to stick the tape to the floor.

Then before I laid the insulation onto the subfloor, I laid 500gauge plastic sheeting on top of the subfloor and tapped it to the bottom of my plastered insulated plasterboard using more airtight tape around every single wall.

Then laid my insulation, UFH pipes and poured screed

rampantbunny

miller_63 wrote: »

The tape is well over the DPM line. This is glued to the wall and to the insulation slab taking care to leave a movement crease in the tape itself.

Why would the screed need to 'bond' to the membrane any more than what it does once its sat and cured over it? The screed is airtight itself on the same lines as your plaster line.

Fair enough in each to their own detail, I responded with how it worked for us. I guess your trying to achieve Passive Standard ACH or lower if your concerned about carpenter nails into wall for skirting board for air ingress?

I might be missing something in your detail, but isn't there a chance of air ingress at the blockwork which lies beside the insulation boards, or have you parge coated these? Is there not also a chance of air ingress at the DPC line in your internal blockwork?
If there is air ingress, then it will circulate through the boards and up under your screed. Is there an assumption that the screed lying on the insulation does not allow any air to move from underneath and between the insulation to the junction the screed makes with the wall?

If air gets between your screed and insulation, and is able to move towards the perimeter then the tape line is not effective. The screed itself will not abut the wall and stick to it, as there is perimeter insulation to consider, so there is a path for air ingress/egress. Are you relying on the weight of the screed on the insulation board to compress against the tape and be airtight?

Re. skirting board holes; I'm not trying for passive house standard airtightness but I am targeting a best figure possible. Protecting the AT layer in places where I have total control is where I'm at right now. I've been accumulating what I see people refer to as 'negligible' holes since the AT membrane was installed, but IMO, when combined these all amount to a non-negligible hole. I need to 'save' some airtightness where I can, to mitigate against those other negligible and not so negligible holes that I can't fix.


Did I read in another thread that you've had your blower door test done got a very good result? If so, well done. Proves there's nothing wrong with your approach so I'd still like to get my head around how that junction you have works.

ht9zni1gs28crp

miller_63 wrote: »

The screed is airtight itself on the same lines as your plaster line.

As already stated, the screed itself is airtight, its of similar make up as your plaster airtight line!

I presume you have all your details in drawings in front of you, post us up a picture of your ground floor interface detail. I really cant see where your concern is that air is going to circulate beneath the screed

rampantbunny

miller_63 wrote: »

As already stated, the screed itself is airtight, its of similar make up as your plaster airtight line!

miller_63 wrote: »

I presume you have all your details in drawings in front of you, post us up a picture of your ground floor interface detail.

Nope, don't have details for this hence the thread. If I had detail, I'd possibly still be here looking for potentially better/alternative ways.

miller_63 wrote: »

I really cant see where your concern is that air is going to circulate beneath the screed

See attached. The line in red shows air ingress through un-parged blockwork, plus at the DPC line which is a common leak point I've been told.
If the air can reach the location of the red arrow then there is air ingress and egress from the building unless (my earlier question) the weight of the screed acting downwards (black downward arrows) seals this area.

I'm not poking holes (geddit) in your approach, just curious as to how it works.

ht9zni1gs28crp

rampantbunny wrote: »

See attached. The line in red shows air ingress through un-parged blockwork, plus at the DPC line which is a common leak point I've been told.
If the air can reach the location of the red arrow then there is air ingress and egress from the building unless (my earlier question) the weight of the screed acting downwards (black downward arrows) seals this area.

I'm not poking holes (geddit) in your approach, just curious as to how it works.

Where is your Radon membrane in that detail? Once you have the slab sealed to the airtight line that's it. Little to zero air is circulating under your slab. the insulation is double layered set staggered joints plus with weight of screed there is no where for air to move through...

Poking holes (i get it now my turn) how on earth have you an airtight or zero cold bridge strategy without any scaled details? :eek:

rampantbunny

miller_63 wrote: »

Where is your Radon membrane in that detail? Once you have the slab sealed to the airtight line that's it. Little to zero air is circulating under your slab. the insulation is double layered set staggered joints plus with weight of screed there is no where for air to move through...

Poking holes (i get it now my turn) how on earth have you an airtight or zero cold bridge strategy without any scaled details? :eek:

Radon barrier is under raft.

I've come across details of this junction from various sources. Most detail taping from plastered wall to screed.
I posted this method in response to another forum member previously. Another approach, tape over the DPC line, parge coat the lower block courses, plaster from DPC line up. I haven't come across your detail before hence curiosity.

I inherited my engineer courtesy of architect. Their combined interest in my build is less than adequate so now the less input both have the more comfortable I am based on previous experience.
How have I zero cold bridge and airtight strategy, simples; not listening to my professionals, reading articles on boards, passive house sites etc.

BarneyMc

Here's what my engineer said:

"The need is to seal the joint between the floor and the wall, as you have yet to install the final screed and yet to plaster the walls the best option is to lay the floor and then seal the wall/floor joint before plastering. This will ensure the plaster over laps the seal with the optimum result.

If timeframes don't allow for the above the next best option is to seal the wall to floor joint after plastering and after the floor is installed."

As I'll be plastering (in about 2 weeks time) I'll be going with option 2. I will look into how to minimise damage like gluing the skirting instead of nailing. You're both way ahead of me lads in your understanding of detail but very interested nonetheless.

BarneyMc

Can anyone recommend (PM) what tapes I can use for my floor to wall junction? This will be applied after walls are plastered and floors go in. Is it an easy detail to apply or best left to a professional? My air tightness guy said it would work out at approx €6 per meter! Thanks.

Tom Hagen

BarneyMc wrote: »

Can anyone recommend (PM) what tapes I can use for my floor to wall junction? This will be applied after walls are plastered and floors go in. Is it an easy detail to apply or best left to a professional? My air tightness guy said it would work out at approx €6 per meter! Thanks.

hey barney did you apply airtight tape from concrete floor to block wall junction? did it stick to the floor ok? what size mm tape did you use

BarneyMc

Tom Hagen wrote: »

hey barney did you apply airtight tape from concrete floor to block wall junction? did it stick to the floor ok? what size mm tape did you use

Yip although it was done by my airtightness guy. He cleaned the floor and applied a primer before taping. Not sure the mm size but it had to cross a 50mm perimeter insulation strip. I'll have a look tomorrow and let you know. This pic should give you a good idea.

Tom Hagen

BarneyMc wrote: »

Yip although it was done by my airtightness guy. He cleaned the floor and applied a primer before taping. Not sure the mm size but it had to cross a 50mm perimeter insulation strip. I'll have a look tomorrow and let you know. This pic should give you a good idea.

Thanks. Is that done before you applied the final skim coat? Or what stage was that plastering at

BarneyMc

Tom Hagen wrote: »

Thanks. Is that done before you applied the final skim coat? Or what stage was that plastering at

For me it was done post skim and post liquid screed floor. This can all be done, as far as I know, pre-plastering and pre-liquid screed and might be a better job as it's very protected.

Calahonda52

http://www.boards.ie/vbulletin/showthread.php?p=100161092 may add value to TH

Tom Hagen

BarneyMc wrote: »

For me it was done post skim and post liquid screed floor. This can all be done, as far as I know, pre-plastering and pre-liquid screed and might be a better job as it's very protected.

My finished floor screed is poured already i did a one pour floor, so i plan to apply airtight tape to floor-wall junction at the bottom and wall-ceiling junction at the top of the rooms , i will apply it after the scratch coat is done but before i final skim the walls. I hope this will be ok?

BarneyMc

Tom Hagen wrote: »

My finished floor screed is poured already i did a one pour floor, so i plan to apply airtight tape to floor-wall junction at the bottom and wall-ceiling junction at the top of the rooms , i will apply it after the scratch coat is done but before i final skim the walls. I hope this will be ok?

BEFORE I would think is better. Anyone?

Tom Hagen

BarneyMc wrote: »

BEFORE I would think is better. Anyone?

ya true actually. I must get onto my a/t guy see what he thinks. thanks

BryanF

BarneyMc wrote: »

BEFORE I would think is better. Anyone?

After first scud, but plasterer needs to run trowel to make surfac smooth at AT tape locations