Spray alternative to parge lining an internal block wall.

[epsilonGreedy]

I am currently juggling options for creating a relatively air tight brick and block 2 story house. 

 

• The simplest option would be facing brick 100mm + woven insulation batts 100mm + medium density block 100mm + wet plaster. Not sure this delivers a decent enough U value.
• Increasing the cavity to 150mm will create problems if I opt to mount my wooden sash windows deep with a full 100mm facing brick reveal, i.e. most of the 175mm thick window frame would be sitting over cavity insulation.
• Another option would be to seal the inner face of the block wall and then add wood battens with 25mm of insulation finished off with screw fixed dry lining.

 

Right now I favour the last option but a 6mm parge coat of the entire inner face of the internal blockwork sounds like a monmouth job. Would the spray application of a gooey thick internal garage wall paint seal the blocks prior to my final layer of battens and insulation?

[Russell griffiths]

Couple of things, can you not just improve on the insulation in the cavity ?

EPS beads, you need to be very careful with cavity insulation and bricklayers it rarely gets fitted well

 

if you enlarge the cavity you will need a cavity closer at the window reveal so your window can sit anywhere you want, how about just cover 10mm of brick with the frame and the rest over the closer 

 

regarding the air tightness just look for a topic recovering academic put up and you will see the replies about parge coats and hopper guns that you can spray render with. Or just use a broom head simple, would take 1 bloke a couple of days to do a whole house

 

regarding insulation costs, just think how quick the brickwork will go up without faffing with all that sodding insulation, been there done that, won’t do it again. 

[PeterW]

I would go 

 

100mm brick

175mm cavity (widest before ties get expensive) blown EPS

100mm medium block

Bonding parge coat

25mm batten Infil with 25mm PIR

Board

Skim

 

That is a 415mm wall which is pretty thick but still uses all standard lintels etc. 

 

Anything over that, go TF

 

 

[Declan52]

Option 2. 

Make the cavity as wide as you can , 150mm -175mm. Get beads blown in. Under no circumstances get the brickies to put in cavity batts. Just don't. Make your build as simple as you can  and let the guys with trowels build and let the insulation guy do his thing.

As far as sealing the blocks up it's either a parge coat with plasterboard stuck to the wall or wet plaster with a scratch coat and skim finish.

Parge coat is just a sloppy mix of sand cement put on with a roller or brush. It's a messy job but easily done.

[Ryan85]

34 minutes ago, Declan52 said:

Option 2. 

Make the cavity as wide as you can , 150mm -175mm. Get beads blown in. Under no circumstances get the brickies to put in cavity batts. Just don't. Make your build as simple as you can  and let the guys with trowels build and let the insulation guy do his thing.

As far as sealing the blocks up it's either a parge coat with plasterboard stuck to the wall or wet plaster with a scratch coat and skim finish.

Parge coat is just a sloppy mix of sand cement put on with a roller or brush. It's a messy job but easily done.

Second that.. Do not use cavity batts. Heard horror stories in relation to these. Moisture seeping through etc. 

[nod]

1 hour ago, epsilonGreedy said:

I am currently juggling options for creating a relatively air tight brick and block 2 story house. 

 

• The simplest option would be facing brick 100mm + woven insulation batts 100mm + medium density block 100mm + wet plaster. Not sure this delivers a decent enough U value.
• Increasing the cavity to 150mm will create problems if I opt to mount my wooden sash windows deep with a full 100mm facing brick reveal, i.e. most of the 175mm thick window frame would be sitting over cavity insulation.
• Another option would be to seal the inner face of the block wall and then add wood battens with 25mm of insulation finished off with screw fixed dry lining.

 

Right now I favour the last option but a 6mm parge coat of the entire inner face of the internal blockwork sounds like a monmouth job. Would the spray application of a gooey thick internal garage wall paint seal the blocks prior to my final layer of battens and insulation?

Large coat isn’t worth doing yourself One plasterer will easy cover a 100 mtrs in a day

[bissoejosh]

1 hour ago, Declan52 said:

 

1 hour ago, Declan52 said:

Option 2. 

Make the cavity as wide as you can , 150mm -175mm. Get beads blown in. Under no circumstances get the brickies to put in cavity batts. Just don't. Make your build as simple as you can  and let the guys with trowels build and let the insulation guy do his thing.

 As far as sealing the blocks up it's either a parge coat with plasterboard stuck to the wall or wet plaster with a scratch coat and skim finish.

 Parge coat is just a sloppy mix of sand cement put on with a roller or brush. It's a messy job but easily done.

 

I agree. 

 

I've just done a 200mm cavity filled with batts all built myself. No chance I would let someone else do it as it's far too easy to skip the insulation detailing. If I'd known at the time I'd have done EPS beads - no covering up insulation, less cavity cleaning and so much quicker. 

 

2 hours ago, epsilonGreedy said:

 

• Increasing the cavity to 150mm will create problems if I opt to mount my wooden sash windows deep with a full 100mm facing brick reveal, i.e. most of the 175mm thick window frame would be sitting over cavity insulation.

 

Ply framed box sitting across the cavity and either resting on the outer leaf (10-15mm) or have it stop short. DPC wherever it touches blockwork.

Window fits within the box and airtightness etc is much simpler. 

Edited April 28, 2018 by bissoejosh

[epsilonGreedy]

56 minutes ago, nod said:

Large coat isn’t worth doing yourself One plasterer will easy cover a 100 mtrs in a day

 

 

Interesting... for this seal-only task does a "parge coat" mean the same thing to a plasterer e.g. slap/brush on a runny mortar mix as suggested earlier in this thread? I don't want to pay for an over specified plastering job which is 6mm thick when a diy grunt work non cosmetic finish will do.

[nod]

I normally use the bagged stuff

Parge coat plus Helps with sound also

5 mil thick about 5 mtrs per bag Bit more of blockwork is neat and pointed Normally takes me about 15 minutes to use a four bag mix 

[epsilonGreedy]

1 hour ago, nod said:

I normally use the bagged stuff

Parge coat plus Helps with sound also

5 mil thick about 5 mtrs per bag Bit more of blockwork is neat and pointed Normally takes me about 15 minutes to use a four bag mix 

 

 

Ok so quite a different finish to the alternative of brushing on a runny mortar or my original idea of spraying an internal garage wall paint just to fill most of the surface voids.

 

When you say helps with sound, is this sound attenuation from outside the house or inter room sound bleed? With my plot the only external sound problem is noisy wood pigeons. 

Edited April 28, 2018 by epsilonGreedy

[epsilonGreedy]

1 hour ago, bissoejosh said:

Ply framed box sitting across the cavity and either resting on the outer leaf (10-15mm) or have it stop short. DPC wherever it touches blockwork.

Window fits within the box and airtightness etc is much simpler. 

 

 

I need to describe the sash window frame in more detail. The objective is to hide half of the vertical weight boxes behind the facing brick skin hence the whole of the outer face of the window frame will be set back the full width of a facing brick. To achieve this the art stone sill will need to be wide enough so that 50mm will overhang backwards over the cavity, the wooden sill of the sash will sit on a raised ledge moulded into the art stone sill and the drip gully of the wooden cill will project forward of the raised ledge.

 

About 70mm of the rear of the wooden from will rest on the inner blockwork.

 

The current architect window fitting diagram shows the sash window frame within the facing brick aperture and set back only 25mm from the front face of the facing bricks. The window specialist claims this is not historically accurate for a wannabe mock 200 year old newbuild. He also added that a full brick width reveal provides a lot more weather protection for a wood sash window.

 

Tucking a good part of the weigh boxes behind the facing brick reveal means that more of the brick aperture can be filled with glass.

[ToughButterCup]

9 hours ago, epsilonGreedy said:

[...]

when a diy grunt work non cosmetic finish will do.

 

You callin' me a DIY grunt then, eh? Come over 'ere and say that, pal.... (and we'll go for a pint ? )

[PeterW]

7 hours ago, epsilonGreedy said:

Tucking a good part of the weigh boxes behind the facing brick reveal means that more of the brick aperture can be filled with glass.

 

What you are describing there is a traditional sash installation but you have a problem if you want to recreate it. 

 

Traditionally, the sash boxes and the outer frame was built into the skin as the building was constructed, and invariably the sash frame became a structural part of the building by acting as a lintel unless there were stone mullions supporting the stone head. 

 

If you look carefully at a traditional box sash, the brick or stone outer skin is invariably narrower than the inner skin, and there may well be a splay internally to maximise the light into the building. 

 

From what you are describing, you will need to build the inner and outer window apertures at different sizes to allow the windows to be installed from the inside, pushing them tight up against the outer skin. This is going to need some very careful detailing as you won’t be able to use a profile for the outer skin opening as the brickworks will need to be fully pointed on the inner reveal. 

 

Have the architect and the window specialist spoken about any of this as it sounds like the architect has designed something one way, and the window supplier is designing something different and the two may not work together which will be a very costly mistake !

 

[Brickie]

5 minutes ago, PeterW said:

the sash frame became a structural part of the building by acting as a lintel

I’ve never come across this myself. A timber Lintol,typically 4x2 has been used on the inner skin to span the opening on the inside,with an arch on the outside,with every single solid wall check reveal detail I’ve worked on (& there were hundreds in my demolition days.)

[nod]

9 hours ago, epsilonGreedy said:

 

Ok so quite a different finish to the alternative of brushing on a runny mortar or my original idea of spraying an internal garage wall paint just to fill most of the surface voids.

 

When you say helps with sound, is this sound attenuation from outside the house or inter room sound bleed? With my plot the only external sound problem is noisy wood pigeons. 

Using sound coat would help seal your block and block out external sound Though there is nothing to stop you putting it on internal block walls But most of the sound will pass through the doorway 

 Your looking at £3.20 per mtr supply and fix

 

Years ago when D&D came in we would put a ten mill sand and cement coat on the party walls

 

Painting a slurry on is very messy and slow and would make little difference to sound