How many props...

[tony1851]

To assuage the OP's worries, here is a 4.5m opening, 4 strongboys, a few props under the floor; no method statements, clipboards, CDM or hi-vis around. Job done, no problems. Most of this is down to experience.

 

[kazuya]

cAtLeYx ok you have a degree in construction but reading some of your posts personally i think you tend to overthink stuff, its not rocket science, most of the guys on here do this stuff day in day out and can look at a wall and say straight away thats 4, 5 or 6 or however many without having to even reach for a tape measure.
i bet your really fun to work with on site

 

[kazuya]

To assuage the OP's worries, here is a 4.5m opening, 4 strongboys, a few props under the floor; no method statements, clipboards, CDM or hi-vis around. Job done, no problems. Most of this is down to experience.

never mind all that, why is he allowed on site with no face

 

[tony1851]

To assuage the OP's worries, here is a 4.5m opening, 4 strongboys, a few props under the floor; no method statements, clipboards, CDM or hi-vis around. Job done, no problems. Most of this is down to experience.

never mind all that, why is he allowed on site with no face

Because like me, he's an ugly $od! (only joking!)

 

[drpepe]

The spacing of a prop or strongboy depends on the type of wall construction among other things. I've done jobs like this on different types of walls such as Bungaroosh, Random stone, 9 inch solid, cavity cement or lime mortar and a judgement has to be made on site. Many of the houses round here are 20 inch stone so require a bit more care when propping.

Apologies for butting in - we're planning a 4.1m opening in a stone built terrace c1901 (wall about 40cm thick).

Presumably this would require a lot more planning, support than an equivalent brick span?

Is there anything I should be looking out for / discussing with my builder about this?

 

[ree]

"Is there anything I should be looking out for"- yes, starting a new thread so that this post doesn't become as entangled as your previous posts.

You might also post pics of the proposition's interior and exterior?

And research the knock-thro variables on here.

 

[^woody^]

Because like me, he's an ugly $od!

More likely a cash job. (and ugly)

Is that all sitting on 130mm of pier? I like it.

 

[stuart45]

The spacing of a prop or strongboy depends on the type of wall construction among other things. I've done jobs like this on different types of walls such as Bungaroosh, Random stone, 9 inch solid, cavity cement or lime mortar and a judgement has to be made on site. Many of the houses round here are 20 inch stone so require a bit more care when propping.

Apologies for butting in - we're planning a 4.1m opening in a stone built terrace c1901 (wall about 40cm thick).

Presumably this would require a lot more planning, support than an equivalent brick span?

Is there anything I should be looking out for / discussing with my builder about this?

Looking at the pictures of your house the coursed stonework on those Edwardian houses in Bristol is usually tied into brickwork on the inside which makes the walls a lot more stable than a Random rubble wall.
Ideally you want a builder that you have confidence in. If someone has a builder whose work they have to question on an internet forum it may be worth changing your builder.

 

[cAtLeYx]

My point has never been about competent builders, I have met thousands of outstanding tradesmen. The fact that I'm no fun is irrelevant. And yes, maybe not that great looking.! The point is being missed here. The OP asked if 5 props were sufficient. Yes maybe, maybe not but the fact still remains that this needs to be evaluated correctly using a written safe system of work and not just apply a standard rule of 1 prop per meter just because its how we've always done it. There is now legislation in place for domestic clients who appoint a single contractor, I wonder how many general builders understand their responsibilities and the outcome if failing to comply becomes apparent. Of course this will only become an issue when something goes wrong.

In support of this
http://www.designingbuildings.co.uk/wiki/CDM_for_self-builders_and_domestic_clients
http://www.hse.gov.uk/construction/faq-temporary-works.htm
http://www.strongboy.co.uk/index.php?id_cms=6&controller=cms

Should we as a collective group not be offering professional advise.

 

[tony1851]

Because like me, he's an ugly $od!

More likely a cash job. (and ugly)

Is that all sitting on 130mm of pier? I like it.

No; the props remained until a new 1 brick x 1 brick pier was built.

 

[^woody^]

If someone has a builder whose work they have to question on an internet forum it may be worth changing your builder.

Or the builder changing their customer?

 

[stuart45]

If someone has a builder whose work they have to question on an internet forum it may be worth changing your builder.

Or the builder changing their customer?

I don't mind anyone checking my work on here woody, as I'll sign in with a different username and tell them what a great job I'm doing.

 

[^woody^]

I wonder how many general builders understand their responsibilities and the outcome if failing to comply becomes apparent

CDM, and the safe systems of work you refer to, were initiated for and only intended as employment regulations to protect employees in the course of their employment.

They are not directly intended as a benefit to the customer or anyone outside of that employment relationship. Although, as is common, the intent has become blurred over time.

 

[stuart45]

When I was a nipper I used to prop up OK but I did whip the acrows out a bit early a few times. Had to put a door in an internal load bearing wall once and caused the floor to drop a bit. The chippie was a real perfectionist and couldn't understand why he got his floor out but I might have forgotten to mention it to him.

 

[RonnyRaygun]

And yes, maybe not that great looking.!

They weren't talking about you, they were talking about him:

Anyway, we know what you look like: