Blockwork going up first

[MortarThePoint]

Sometimes what's difficult as a first time selfbuilder is when things differ from how you thought things would progress and being unsure if that's OK. I had expected inner and outer leaves to rise at the same time, but the brickies are planning to do all the inner leaf blockwork first and then the outer leaf brickwork. Is there anything wrong with this approach? I had expected the inner leaf to lag the outer leaf to help them keep the cavity clear, but as long as they manage to keep the cavity clean is there any other worry in the approach they are taking?

 

[LA3222]

On my own self build journey I have learned to mellow out a bit. There is the way you expect things to be done and then there is the way that things are done. The disconnect between the two caused me a lot of angst during the early stages. 

 

If it works, it works. Dont get too hung up on the how, let them do what they do, if the house stands then all is good with the world.

Edited August 10, 2020 by LA3222

[MortarThePoint]

1 minute ago, LA3222 said:

On my own self build journey I have learned to mellow out a bit. There is the way you expect things to be done and then there is the way that things are done. The disconnect between the two caused me a lot of angst during the early stages. 

 

If it works, it works. Dont get too hung up on the how, let them do what they do, if the house stands then all is good with the world.

 

I've been pretty relaxed about it, but then spooked myself that perhaps I should have thought about it a bit more. I saw the NHBC guidance below that says not more than 6 block courses and they are going up to 9.

 

[Mr Punter]

I know they like to do this but I prefer the brickwork first because there is loads more mortar to clean up from the inside face.

[MortarThePoint]

I worded my initial post poorly. The brickies are planning to do all the inner leaf blockwork to 9 courses high. They then plan to do the outer leaf brickwork.

[Russell griffiths]

Ask them to install coring holes so the cavity can be cleaned out. 

[MortarThePoint]

26 minutes ago, Russell griffiths said:

Ask them to install coring holes so the cavity can be cleaned out. 

 

Yes that would help, but doesn't protect the ties from snots unfortunately.

[epsilonGreedy]

13 hours ago, MortarThePoint said:

Is there anything wrong with this approach?

 

 

You should be alert to stability concerns during high winds. Mortar continues to harden and the adhesive bond strengthens over the first two weeks.

 

My brickie took the ground floor outer facing bricks up to 5ft then laid the inner blocks up to the same height. He kept an eye on the weather and half the time the single skin walls were braced with wood. He did the reverse above the first floor and took the inner block wall upto nose height. Scheduling of scaffold lifts will sometime influence the sequence of work. Fitting cavity lintels are another stage where the wall heights need to be synchronized.

 

My semi retired building advisor later told me he noticed the height of the unsupported blocks wall when he drove past the site and he was concerned until he visited site to advise on chimney corbelling at which point he noticed all the internal temporary bracing said it was ok.

 

Like @LA3222 I have discovered a first time self build is a difficult journey involving watching exert trades do things that fall short of internet forum best practice and deciding to intervene and request rectification.

Edited August 11, 2020 by epsilonGreedy

[Declan52]

7 course high is normal height as that's how high is comfortable to lift a block up to that height. But it won't make no difference to the wall. It's only a small run with the returning walls so the wind wouldn't move it.

[MortarThePoint]

I asked my BCO and he said he'd prefer 1.6m max. I spoke to the brickies and they were concerned that the scaffolders wouldn't want to do their internal birdcage that low. I checked with the scaffolders and they said that was fine. All the rest will be stopping at 7 courses which I am happy about and the brickies are happy too as they won't have to visit each section twice before the first internal scaffold lift, they'll just be doing more off the internal scaffold (~1.6m to ~2.7m).

 

To avoid snots in the cavity, the brickies are planning to have a timber at the top of cavity resting on the ties (to pull out vertically) and one at the bottom of cavity they can pull out sideways. I'm sure we are going to have words at some point about keeping the cavity clean, but hopefully it won't be too bad.

[epsilonGreedy]

26 minutes ago, Declan52 said:

7 course high is normal height as that's how high is comfortable to lift a block up to that height. But it won't make no difference to the wall. It's only a small run with the returning walls so the wind wouldn't move it.

 

 

Your comment highlights another issue which is regional variations in building practice.

 

A year ago you told us it is normal in Northern Ireland to use 1:3 mortar for all walls whereas in mainland England this would be considered bad form. Also I think in NI you tend to use medium/heavy blocks because this is what is manufactured locally and available more cheaply? As a result your freshly laid wall starts off with a strength advantage. In mainland England damage from wind force is a higher concern.

Edited August 11, 2020 by epsilonGreedy

[Declan52]

Nothing to do with the motar or blocks the wall is just a short run so less likely to twist in the wind unless it's a storm which could blow over any wall. 

[epsilonGreedy]

15 minutes ago, Declan52 said:

Nothing to do with the mortar or blocks the wall is just a short run so less likely to twist in the wind unless it's a storm which could blow over any wall. 

 

 

I believe the OP is looking for general advice for the remainder of his build and not specific comment on the garage in the photo.

 

A strong 1 in 3 mortar hardens more quickly and at any point in the first two weeks the wall will be stiffer, as a result in NI you suffer less wind damage incidents. Hence you are unaware of the issue.

[Declan52]

Not sure where you are getting your info from but the wind most definitely blows plenty here.  Have had quite a few walls blow over. It happens a lot on every site everywhere.

The mix strength depends on your sand as well and most of our sand would come from Lough Neagh so its not the best for motar. If you can get it from one of the pits then it's 5 in 1 but it's much more expensive so Lough sand is what's mostly used. 

[PeterW]

Sand has a surprising impact on the mortar - we use a “grey” Lincolnshire sand rather than the red Mansfield sand as the one that comes from further west tends to be quite grainy and doesn’t make as good a mortar. With new bricks then a 5:1 is normal round here, but for reclaims (which we do a lot of) then we use 5:1:1

sand cement and hydrated lime. 

[Russell griffiths]

5 hours ago, MortarThePoint said:

 

Yes that would help, but doesn't protect the ties from snots unfortunately.

Lean over the cavity every night and check with a torch, knock any off with a bit of stick. 

 

You shouldn't really get snots with a wire tie. 

[Declan52]

Our Lough sand is too clean so it hasn't much larger particles in it so won't hold water. Apparently there is over a mile deep of sand in Lough Neagh, largest lake in the UK, so we will be using it for many many years to come. It's brilliant for concrete and for drainage on football pitches etc but just not great for mortar but it's very cheap so it's used a lot. I can get it a mile from my house at around £10 a tonne if I collect in a trailer and cheaper if I buy it in full lorry load. Also as the same company will do concrete you can make a good saving if you let them supply it as well.

Pit sand will have dirt which helps keep it from going like fluff.

[MortarThePoint]

1 hour ago, Russell griffiths said:

Lean over the cavity every night and check with a torch, knock any off with a bit of stick. 

 

You shouldn't really get snots with a wire tie. 

 

Sounds like a plan. I'll also try to keep them on their toes but don't enjoy having to push people for their best work.

[epsilonGreedy]

21 hours ago, Declan52 said:

Our Lough sand is too clean so it hasn't much larger particles in it so won't hold water. Apparently there is over a mile deep of sand in Lough Neagh, largest lake in the UK, so we will be using it for many many years to come. It's brilliant for concrete and for drainage on football pitches etc but just not great for mortar but it's very cheap so it's used a lot.

 

 

Ah ha, this explains a mystery from 1 year ago, regional specifics is the explanation . Back then I challenged another forum notable who suggested that 3:1 mortar was inherently superior to 5:1 mortar and that anything less than 3:1 mortar was dubious penny pinching. A 17 year old trainee brickie and the NHBC know this is not true, yet at the time you said in NI 3:1 was used for above dpc walls. Given what you have told us in this thread it appears 3:1 is used to compensate for the poor quality sand.

 

22 hours ago, Declan52 said:

Not sure where you are getting your info from but the wind most definitely blows plenty here.  Have had quite a few walls blow over. It happens a lot on every site everywhere.

 

 

It sounds like you now agree that when building high single skin walls a self builder should be alert to windy weather particularly when the mortar is still hardening. 

Edited August 12, 2020 by epsilonGreedy