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Solid blocks flat

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  • 30-07-2018 9:29pm
    #1
    Registered Users Posts: 141 ✭✭


    Hi, quick question. Relative of mine is getting an extension done at the moment and the builder started laying blocks today. The block he is using are solid 4inch block and they are laid flat. She said that builder is doing that and putting insulation boards on the inside as in no other leaf of blocks. Is this normal/ok as I always thought the norm would be 2 rows of blocks on there side with insulation in the middle.


Comments

  • Registered Users Posts: 6,136 ✭✭✭screamer


    Expensive way to build. Blocks on the flat are much dearer to build but are used when going to be load bearing. Dunno about no second leaf though... Could be a recipe for damp etc... is she getting it built on the cheap? Genuine question.


  • Registered Users Posts: 141 ✭✭bambam26


    screamer wrote: »
    Expensive way to build. Blocks on the flat are much dearer to build but are used when going to be load bearing. Dunno about no second leaf though... Could be a recipe for damp etc... is she getting it built on the cheap? Genuine question.

    Not to sure about the price tbh, reputable firm doing the job who have done a lot of work in the area and within her circle of friends, I have just never seen something build out that before all be it I have very limited experience in seeing something being built.


  • Closed Accounts Posts: 844 ✭✭✭H.E. Pennypacker


    Are there plans? If so, does the builder’s approach match?


  • Registered Users Posts: 141 ✭✭bambam26


    Are there plans? If so, does the builder’s approach match?

    No plans it’s just a simple open plan extension about 20sq mtrs no wall removal or anything like that.


  • Closed Accounts Posts: 6,820 ✭✭✭smelly sock


    bambam26 wrote: »
    No plans it’s just a simple open plan extension about 20sq mtrs no wall removal or anything like that.

    That wont go down well on here....


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  • Moderators, Society & Culture Moderators Posts: 38,940 Mod ✭✭✭✭Gumbo


    I built my extension with solids on the flat.
    It’s more expensive than cavity blocks but it’s a better system depending on how you treat the inside.

    I fixed 100mm insulaation direction to the Sand/cemented internal face then put 50mm batters and fixed my plasterboard to the battens. This left me with a service cavity to run my electrical and plumbing through.

    My insulation layer remained untouched even after the trades carried out their end. I also taped all joints of the insulation.

    Solids on the flat are better for air tightness, sound transmission and can be utilized to the load bearing steel beam if required.

    The builder may be also considering next door building an extension in the future and this ensures a force safety party wall.


  • Registered Users Posts: 6,136 ✭✭✭screamer


    bambam26 wrote: »
    Are there plans? If so, does the builder’s approach match?

    No plans it’s just a simple open plan extension about 20sq mtrs no wall removal or anything like that.

    Yeah I'd ask him what guarantee he'll give with it, cavities are used for a reason and in a damp climate like Ireland, are imho necessary. Sounds like the builder is just trying to save time, but his time saving methods are going to be your friends house.....ask him why he's building it that way and what come back she has if it's no good. Remember it could be years down the line that you'd see issues with damp etc....building rarely goes spectacularly wrong in the first decade anyway


  • Subscribers Posts: 41,415 ✭✭✭✭sydthebeat


    bambam26 wrote: »
    No plans it’s just a simple open plan extension about 20sq mtrs no wall removal or anything like that.

    So if you don't tell then how to build it, your at the builders mercy.

    Not sure how you managed to get accurate prices without plans or specifications


  • Moderators, Society & Culture Moderators Posts: 38,940 Mod ✭✭✭✭Gumbo


    screamer wrote: »
    Yeah I'd ask him what guarantee he'll give with it, cavities are used for a reason and in a damp climate like Ireland, are imho necessary. Sounds like the builder is just trying to save time, but his time saving methods are going to be your friends house.....ask him why he's building it that way and what come back she has if it's no good. Remember it could be years down the line that you'd see issues with damp etc....building rarely goes spectacularly wrong in the first decade anyway

    The builder is by no means trying to save time. Building solids on the flat takes longer as you can’t lay as many blocks in the day, stops after certain heights etc

    If the builder wanted to save time and money, he would have used cavity blocks.


  • Registered Users Posts: 141 ✭✭bambam26


    kceire wrote: »
    I built my extension with solids on the flat.
    It’s more expensive than cavity blocks but it’s a better system depending on how you treat the inside.

    I fixed 100mm insulaation direction to the Sand/cemented internal face then put 50mm batters and fixed my plasterboard to the battens. This left me with a service cavity to run my electrical and plumbing through.

    My insulation layer remained untouched even after the trades carried out their end. I also taped all joints of the insulation.

    Solids on the flat are better for air tightness, sound transmission and can be utilized to the load bearing steel beam if required.

    The builder may be also considering next door building an extension in the future and this ensures a force safety party wall.
    This sounds like what he is doing by what she told me
    sydthebeat wrote: »
    So if you don't tell then how to build it, your at the builders mercy.

    Not sure how you managed to get accurate prices without plans or specifications
    Don't know the ins and outs of how it was priced, I was just wondering about how the blocks where being laid as I had not seen it before but as I said I have not seen many house extensions being built


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  • Moderators, Society & Culture Moderators Posts: 38,940 Mod ✭✭✭✭Gumbo


    bambam26 wrote: »
    This sounds like what he is doing by what she told me


    Don't know the ins and outs of how it was priced, I was just wondering about how the blocks where being laid as I had not seen it before but as I said I have not seen many house extensions being built

    If he is doing it the way I done mine, it’s a more expensive, more time consuming process. I done it that way as it was my home, my build, so I wanted it done right.

    There was no point me doing a traditional cavity construction as the house was originally constructed with cavity blood blocks along the side and rear.

    This method requires expensive 200mm screws, battens to be predrilled etc but it’s worth it. I done a vaulted roof extension with 4 skylights and the end is total glass, doors and the triangle above it, and to this day it’s still the warmest room in the whole house. It retains the heat a lot better.


  • Registered Users Posts: 3,724 ✭✭✭Metric Tensor


    Just be aware that without a cavity or any external screening or insulation you are relying completely on the external tender for water tightness. This an in increasingly common reliance in many new builds but I sometimes think it's more by a accident than design in many.

    Relying solely on the external render to prevent moisture from getting to the porous block is risky in exposed locations and/or in the absence of a good plasterer or overall good build quality. This moisture ingress issue was why the cavity wall developed in the first place.

    Many parts of Dublin never went that direction and used a single leaf of cavity block instead - I'm not sure if this was due to the more sheltered nature of cities or the drive to make better profits from construction.

    Properly constructed block on the flat is very good structurally though.


  • Moderators, Society & Culture Moderators Posts: 38,940 Mod ✭✭✭✭Gumbo


    Just be aware that without a cavity or any external screening or insulation you are relying completely on the external tender for water tightness. This an in increasingly common reliance in many new builds but I sometimes think it's more by a accident than design in many.

    Relying solely on the external render to prevent moisture from getting to the porous block is risky in exposed locations and/or in the absence of a good plasterer or overall good build quality. This moisture ingress issue was why the cavity wall developed in the first place.

    Many parts of Dublin never went that direction and used a single leaf of cavity block instead - I'm not sure if this was due to the more sheltered nature of cities or the drive to make better profits from construction.

    Properly constructed block on the flat is very good structurally though.

    Good advice too MT.
    I actually took this advice from yourself on board at the time of my construction, and because my extension was relatively sheltered in the suburb, I went with it.


  • Registered Users Posts: 141 ✭✭bambam26


    Just be aware that without a cavity or any external screening or insulation you are relying completely on the external tender for water tightness. This an in increasingly common reliance in many new builds but I sometimes think it's more by a accident than design in many.

    Relying solely on the external render to prevent moisture from getting to the porous block is risky in exposed locations and/or in the absence of a good plasterer or overall good build quality. This moisture ingress issue was why the cavity wall developed in the first place.

    Many parts of Dublin never went that direction and used a single leaf of cavity block instead - I'm not sure if this was due to the more sheltered nature of cities or the drive to make better profits from construction.

    Properly constructed block on the flat is very good structurally though.
    Thanks for the reply, it is a well sheltered exension and will be finished with pebbel dashing, going to call over today and have a chat with the builder and see exacty what the story is more out of interest than concern, all previous customers of the builder my relative knows where all happy with the work and have had no issues and some are standing over 8-9 years


  • Moderators, Society & Culture Moderators Posts: 38,940 Mod ✭✭✭✭Gumbo


    bambam26 wrote: »
    Thanks for the reply, it is a well sheltered exension and will be finished with pebbel dashing, going to call over today and have a chat with the builder and see exacty what the story is more out of interest than concern, all previous customers of the builder my relative knows where all happy with the work and have had no issues and some are standing over 8-9 years

    Take some pictures and post them up.


  • Subscribers Posts: 41,415 ✭✭✭✭sydthebeat


    bambam26 wrote: »
    Hi, quick question. Relative of mine is getting an extension done at the moment and the builder started laying blocks today. The block he is using are solid 4inch block and they are laid flat. She said that builder is doing that and putting insulation boards on the inside as in no other leaf of blocks. Is this normal/ok as I always thought the norm would be 2 rows of blocks on there side with insulation in the middle.

    id say the first rows of blocks are solid on the flat becuase they are rising walls.... id imagine the blocklayer will switch to cavity block once over DPC level.


  • Registered Users Posts: 3,724 ✭✭✭Metric Tensor


    sydthebeat wrote: »
    id say the first rows of blocks are solid on the flat becuase they are rising walls.... id imagine the blocklayer will switch to cavity block once over DPC level.


    Good spot syd - this is quite possible or even likely unless someone has specifically specified "block on flat"


  • Moderators, Society & Culture Moderators Posts: 38,940 Mod ✭✭✭✭Gumbo


    sydthebeat wrote: »
    id say the first rows of blocks are solid on the flat becuase they are rising walls.... id imagine the blocklayer will switch to cavity block once over DPC level.

    I considered this also, but with 215mm rising walls, how will the builder then add a 100/100/100 system?
    Maybe he will continue above ground with 215 cavity blocks?


  • Registered Users Posts: 3,724 ✭✭✭Metric Tensor


    I'm pretty sure that's what syd meant kc. 215 wall all the way. Block on flat for rising wall and cavity blocks above ground.


  • Moderators, Society & Culture Moderators Posts: 38,940 Mod ✭✭✭✭Gumbo


    I'm pretty sure that's what syd meant kc. 215 wall all the way. Block on flat for rising wall and cavity blocks above ground.

    you'd think I would of seen that.....considering he actually posted it..... :o


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  • Registered Users Posts: 141 ✭✭bambam26


    sydthebeat wrote: »
    bambam26 wrote: »
    Hi, quick question. Relative of mine is getting an extension done at the moment and the builder started laying blocks today. The block he is using are solid 4inch block and they are laid flat. She said that builder is doing that and putting insulation boards on the inside as in no other leaf of blocks. Is this normal/ok as I always thought the norm would be 2 rows of blocks on there side with insulation in the middle.

    id say the first rows of blocks are solid on the flat becuase they are rising walls.... id imagine the blocklayer will switch to cavity block once over DPC level.
    No the block where about 6 rows above DPC and still flat, will take a few pic later and post up


  • Registered Users Posts: 5,890 ✭✭✭Bullocks


    kceire wrote: »
    I considered this also, but with 215mm rising walls, how will the builder then add a 100/100/100 system?
    Maybe he will continue above ground with 215 cavity blocks?

    They could use brick to bring the rising walls to 300 if they wanted


  • Moderators, Society & Culture Moderators Posts: 38,940 Mod ✭✭✭✭Gumbo


    Bullocks wrote: »
    They could use brick to bring the rising walls to 300 if they wanted

    To do that, the brick would have to be tied into the 215 block from foundation up. It wouldn’t be possible to add the brick later.


  • Registered Users Posts: 920 ✭✭✭Ron Burgundy II


    OP, how will the external face of the wall be finished? I've seen houses (passive) been constructed using 225mm block on flat (one leaf only) and finished with 300mm of external insulation and plaster render. Maybe this is what the builder is intending on building?


  • Registered Users Posts: 162 ✭✭moldy_sea


    kceire wrote: »
    I built my extension with solids on the flat.
    It’s more expensive than cavity blocks but it’s a better system depending on how you treat the inside.

    I fixed 100mm insulaation direction to the Sand/cemented internal face then put 50mm batters and fixed my plasterboard to the battens. This left me with a service cavity to run my electrical and plumbing through.

    My insulation layer remained untouched even after the trades carried out their end. I also taped all joints of the insulation.

    Solids on the flat are better for air tightness, sound transmission and can be utilized to the load bearing steel beam if required.

    The builder may be also considering next door building an extension in the future and this ensures a force safety party wall.

    What was the wall make up from outside to inside?

    Was it:
    Render
    EWI (??mm)
    215mm block on flat
    sand + cement
    100mm insulation
    50mm battens
    12.5mm plasterboard

    Happy with the performance? Any issues?


  • Moderators, Society & Culture Moderators Posts: 38,940 Mod ✭✭✭✭Gumbo


    moldy_sea wrote: »
    What was the wall make up from outside to inside?

    Was it:
    Render
    EWI (??mm)
    215mm block on flat
    sand + cement
    100mm insulation
    50mm battens
    12.5mm plasterboard

    Happy with the performance? Any issues?

    Dry Dash
    215mm Block on Flat
    Sand / Cement Render
    100mm PIR Insulation fixed to wall with all joints taped.
    50x50 battens fixed through the insulation to the wall.
    12.5mmPlastrboard
    Skim coat
    Paint

    Happy with result - Yes.
    Its the warmest room In the house despite being the biggest and its open vaulted with the whole gable glazed (4.3m sliding door and triangle glazing above).


  • Registered Users Posts: 157 ✭✭bleaks


    Re-opening an old thread but looking to do something similar. I'll be replacing a garage up and over door with a decent wall that will hopefully be relatively soundproofed (as I'd like use the room for music purposes as well as an office), with a triple glazed timber framed window in the middle. Living in D12, end of terrace ex-corpo, but this is the windy side of the house.

    Should I have any concerns instructing a bricklayer to do the following? I haven't gotten any recommendations for anyone by any friends so it looks like I may have to take a punt on someone to do this.

    From outside to inside - Dimensions are 2240mm(w) by 2040mm(h)


    Flat sand+cement render, painted.

    215mm (4") Solid Block on Flat over DPC at base

    Sand / Cement Render

    Triple Glazed Window (1200mm x1000mm+Cill) I already have the window

    Battens with 50/100mm fiberglass/rockwool insulation - tight on space so might have to go 50mm with 2x2 battens.

    12.5mm x Plasterboard

    Green Glue (This is acoustic/permanently flexible mastic that acts a spring/sound absorber between 2 sheets of drywall - I will provide this)

    15mm Soundbloc

    Skim coat

    Paint

    A few q's:

    1. Is the above a sound plan? (No pun intended!)
    2. Any idea what a fair current price is to pay for the above work (Dublin price unfortunately)?
    3. I have a handy enough mate who is a carpenter. I'm not sure if he has done any brickwork, but would you trust a carpenter to do they above?
    4. Any bricklayer recommendations in Dublin?
    5. Anything else to consider, watch out for? ie, would someone allow me buy the materials and I pay labour to bring the cost down, etc.

    Thanks in advance



  • Registered Users Posts: 7,959 ✭✭✭Rows Grower


    If you're so tight on space you can only do 50mm of insulation I'd put the blocks on edge.

    "Very soon we are going to Mars. You wouldn't have been going to Mars if my opponent won, that I can tell you. You wouldn't even be thinking about it."

    Donald Trump, March 13th 2018.



  • Registered Users Posts: 157 ✭✭bleaks


    As it's for soundproofing more than anything, the thicker the wall the better - so I reckon I'll keep it on the flat. Thanks though.



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