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Hole in external wall...


Carl Fimble

Question

...so I'm gonna be going up a ladder. The wall is made up of breeze blocks, bricks and then harling, so the little stones such into the wall.

I'm not going to be able to match tge colour brilliantly but want to try at least. Not even sure what I need, hence this post.

I know I need to chip off loose bits, clean it up, slap some stuff (mortar?) on and then throw handfulls of the wee stones, bit out of my depth though, or that's the feeling I'm getting anyway. 

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Bricks & Mortar

Post a picture, and I may be able to suggest a likely mix or materials.  And say whether I'd attempt it off a ladder.

The following is how I'd do a small (a square foot or two) patch off a ladder - not anything larger, for which I'd use different tools and scaffold.
Up a ladder, you'll be short of hands.
If you go with a ladder; 
1.  go up and pick out any harling or mortar you need to - pointy/picky hammer. 
2.  mix your mortar - half a bucket is about all you want up the ladder with you.  Can maybe balance the bucket on the ladder, held in by your chest, or hold it in your other hand.  I've a bucket that fits through a rung ahead of me and it gets wedged nearer the rim, which is nice.  4:1 is the recommended ladder angle, but you'll find the bucket easier if you increase this a little ( I mean something like 3.5/1  just a little shallower- but make sure the bottom of the ladder is very secure, perhaps dug into the ground, or have a person (trusted) footing it because the risk with a shallower ladder is the bottom sliding out
2A - whats the block like?  If it looks like it'd suck a lot of water - maybe paint a cement/water slurry on it.  We'd use SBR, but for a wee patch, just mix up pure cement and water like wallpaper paste, and apply with a brush.  This should bond well and prevent the block sucking the water out the mortar too quick.
3.  I'd apply the mortar with a trowel.  just pick up some out of the bucket.  You'll have dampened the blocks first, and done a decent job of mixing it, with plasticiser.  Consistency is all important.  You want a mortar that has some body, but also So, with a trowelful of mortar, just throw it at the wall, using a wrist action like a darts player.  Throw as many as you need, and smooth it out with the back of the trowel.  If the trowel skill is difficult, use your (gloved) hand to pick it up and throw it.  But you still need to smooth it and press it back.  Might need to be quick with the trowel to catch it soon after it lands, to prevent it sliding off.  Need just enough on the trowel that you can land it and its own weight doesn't pull it off the surface.  Don't overtrowel it on the wall - that shiny smoothness you get is because the metal trowel forces the sand down and its replaced by cement particles at the surface - if you overtrowel it can be weak at the back - so just enough to make it smooth and don't worry about a few lines.

For the harling - is it dry dash or wet dash?  The difference in wet dash is the chips are coated in a mortar slurry.  Dry dash will be much better for you.  Assuming its dry dash, I'd consider throwing them by hand - let the mortar set a little, dampen the chips, mix them round and just use your hand.  Harling trowel is better, but the wrist action needs learned, and you don't want to do that up a ladder.  Game is to catch the mortar at the right point and use just enough force to bed the chips halfway in.

Expect to drop a lot of mortar and chips - so dust sheet or cardboard on the ground.

And definitely have  practise on the ground first.

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On 23/12/2019 at 16:27, Bricks & Mortar said:

I assume, since its a modern house, the ceilings are about 2.4m, its 2 storey, so that's about 5m off the ground.  I'd do it off a ladder.
Ideally, I'd rest the ladder somewhere above the hole, so my body was kept back from the workplace, but that's not happening here, since you run out of wall.  Don't suppose you have a ladder standoff, or might be prepared to buy one?  Would also be a nice thing to have if you were ever cleaning those plastic gutters.

Looks like the roof has been shedding water over this area, evidence with the black mould, which might have led to water behing the harling, which might have frozen, expanded, and forced the harling off / damaged the brick.  Can see evidence of a repair to the roof edge.
 

Ladder standoff is a good idea - should add a degree of stability to the ladder too with the splayed top they have, as well as making working and organising tools / materials easier too.

There's signs of mould in places all the way along the edge - might we worth going right along the roofline and make sure the top edge is sealed to minimise any water ingress behind the render top edge, otherwise similar patches will appear and compromise the whole render coat, as you say both existing failure points have started right on the tile line so pretty likely it is water getting behind the render right at the tile line.

 

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Thank you guys!

I'll get onto it as soon as I've cleared my work backlog. 

Scared of the height risk, but it needs done, and I neither trust a tradesman to do a decent job of it, or have the money to give them to sort it. 

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Bricks & Mortar

I assume, since its a modern house, the ceilings are about 2.4m, its 2 storey, so that's about 5m off the ground.  I'd do it off a ladder.
Ideally, I'd rest the ladder somewhere above the hole, so my body was kept back from the workplace, but that's not happening here, since you run out of wall.  Don't suppose you have a ladder standoff, or might be prepared to buy one?  Would also be a nice thing to have if you were ever cleaning those plastic gutters.
Assuming you don't, its gonna be quite tight up the top - but its not a big area.  Maybe find a bucket thats not so big, like a 3kg tile grout tub or something.

You'll want a fair day.  Temp above 5 C and forecast for staying above freezing that night.  Best to get about it in mid-morning, once the temp rises.

THE HOLE ON THE RIGHT
Brickwork looks like it might be crumbling and this may be the underlying cause of the harling falling off.  Give it a few taps with the hammer and see if anything is loose enough to fall off.  If anything does, and it goes deep, you might mortar up that bit first, to bring the surface back out to 10-20mm below the finish level.  Ideally, you want your whole patch to be the same depth,  since you want it to be ready to take the gravel all at the same time - not bouncing off one area and splattering in another.  If you do build it up first, scratch the surface, and leave it several days to let the first coat shrink to avoid any shrinkage cracks coming through to the outside.

THE HOLE ON THE LEFT
Has a crack going out to the corner of the building.  Risk of that section coming off and taking off a piece of the corner, and maybe even round behind the gutter.  Ladder work is even more dangerous at the corner of a building, and I wouldn't fancy your chances of forming a corner or work underneath the gutter.  Therefore, don't pick anything.  Just fill the hole, and rub some mortar into the crack.

You've bought a premixed sand/cement mortar - so my earlier suggestion of mixing pure cement and water as a bonding coat is out.  I think you should try something to help seal those bricks though.    I guess you could try mixing that stuff to a slurry consistency.  Low cement content probably means the sand runs about though.  Could be messy.  Try a 2-3 thin coats.  A disposable coffee cup is good for this.  Wash the brush immediately.

Looks like the roof has been shedding water over this area, evidence with the black mould, which might have led to water behing the harling, which might have frozen, expanded, and forced the harling off / damaged the brick.  Can see evidence of a repair to the roof edge.







 

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Long time lurking
On 17/12/2019 at 19:11, Harley said:

Defo would use a scaffold tower, which I have, hence I'm still posting!

https://www.youtube.com/watch?v=AYmSVazqyQs

https://www.youtube.com/watch?v=np53BJEqx_M

Etc

First time I did it I didn't use the right trowel/technique and it looked rubbish!

PS:  If it's possible, maybe put in a dummy vent!

I think you may need a pasma ticket to hire scaffold towers now 

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6 hours ago, Long time lurking said:

I think you may need a pasma ticket to hire scaffold towers now 

Only for commercial use by the looks of it, it would be somewhat counter productive to prevent DIY'ers access to their hire/use. 

https://www.hirestation.co.uk/tool-hire/Access/Scaffold-Tower-Hire/

A PASMA qualification may be required for commercial use, formal qualifications are not required for domestic DIY applications / users. The PASMA Course: Towers for Users is available from Brandon Hire Station and is designed for personnel who will be assembling, dismantling, moving and inspecting mobile towers. A PASMA Photo Card and Certificate will be issued to successful delegates who complete the theory and practical sessions which have a five year validity period

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The good news is the materials (the dashing material) is most likely local, pick a selection of stones off the existing harling and have a trip round the local builder's merchants for a suitable match. The rest is a render coat underneath - just like a mortar mix with suitable sand / cement mix (you could try a small batch for matching colour mix). Try a test patch with the harling  too on the ground first to work out how to apply the correct amount to correct depth to match, the materials will be as cheap as chips so well worth the time where it is easy to experiment.

Biggest issue for me would be doing it up a ladder this time of year at all, unless you have a good quality ladder with decent wide base / legs you are certainly taking a fairly significant risk - wet - check, slippy - check, inexperienced - check, not the best ladder - likely check, cold - check, heavy materials to carry up and position/hold whilst doing job - check. Look up a few videos on ladder safety first at the very least and check that the ladder/equipment you have is at lest minimally suitable. I pretty much won't do anything up a full size ladder nowadays, small lightweight tower scaffold all the way.

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Kind of related to this - I have some mice or rats in the ceiling space, which means (I think) that they are getting in from the trees next to the house and some hole up high.  I will kill them, but unless I find the hole, the next lot will just come in at some point, and then the dreaded fucking possums who sound like elephants screaming AC.DC when having sex.

So - how do I find and block the hole?  Already cutting the trees back to reduce access...

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17 hours ago, Bricks & Mortar said:

Post a picture, and I may be able to suggest a likely mix or materials.  And say whether I'd attempt it off a ladder.

The following is how I'd do a small (a square foot or two) patch off a ladder - not anything larger, for which I'd use different tools and scaffold.
Up a ladder, you'll be short of hands.
If you go with a ladder; 
1.  go up and pick out any harling or mortar you need to - pointy/picky hammer. 
2.  mix your mortar - half a bucket is about all you want up the ladder with you.  Can maybe balance the bucket on the ladder, held in by your chest, or hold it in your other hand.  I've a bucket that fits through a rung ahead of me and it gets wedged nearer the rim, which is nice.  4:1 is the recommended ladder angle, but you'll find the bucket easier if you increase this a little ( I mean something like 3.5/1  just a little shallower- but make sure the bottom of the ladder is very secure, perhaps dug into the ground, or have a person (trusted) footing it because the risk with a shallower ladder is the bottom sliding out
2A - whats the block like?  If it looks like it'd suck a lot of water - maybe paint a cement/water slurry on it.  We'd use SBR, but for a wee patch, just mix up pure cement and water like wallpaper paste, and apply with a brush.  This should bond well and prevent the block sucking the water out the mortar too quick.
3.  I'd apply the mortar with a trowel.  just pick up some out of the bucket.  You'll have dampened the blocks first, and done a decent job of mixing it, with plasticiser.  Consistency is all important.  You want a mortar that has some body, but also So, with a trowelful of mortar, just throw it at the wall, using a wrist action like a darts player.  Throw as many as you need, and smooth it out with the back of the trowel.  If the trowel skill is difficult, use your (gloved) hand to pick it up and throw it.  But you still need to smooth it and press it back.  Might need to be quick with the trowel to catch it soon after it lands, to prevent it sliding off.  Need just enough on the trowel that you can land it and its own weight doesn't pull it off the surface.  Don't overtrowel it on the wall - that shiny smoothness you get is because the metal trowel forces the sand down and its replaced by cement particles at the surface - if you overtrowel it can be weak at the back - so just enough to make it smooth and don't worry about a few lines.

For the harling - is it dry dash or wet dash?  The difference in wet dash is the chips are coated in a mortar slurry.  Dry dash will be much better for you.  Assuming its dry dash, I'd consider throwing them by hand - let the mortar set a little, dampen the chips, mix them round and just use your hand.  Harling trowel is better, but the wrist action needs learned, and you don't want to do that up a ladder.  Game is to catch the mortar at the right point and use just enough force to bed the chips halfway in.

Expect to drop a lot of mortar and chips - so dust sheet or cardboard on the ground.

And definitely have  practise on the ground first.

Thank you! 

The stones don't look like they've been coated in mortar, so dry dash I think.

Got a bag of ready mixed mortar the other day, will practice with that, and see what sort of colour it dries to. 

Here's a wee cropped photo, as much as my paranoia will allow I'm afraid : 

IMG_20191215_104812~2.jpg

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Bricks & Mortar

Yup - dry dash.
Can't be sure, but looks like someone did this job before.  Is the backing mortar around the hole a slightly different colour?

You might want to test a small bit of the mortar you bought by mixing and letting it dry.  Some cements these days have lots of pulverised ash in them (blame the greenies), which makes them much darker.  But, since there's already a lot of black mould growing in patches, it's up to you how much you care about this.  I wouldn't be worried too much about the colour, as long as its grey.  The mortar will be fine if you're ok with the colour.

Chips look like a 3-6mm white marble.  Sometimes called Essno.  You might find it in builders merchants, or even at B&Q - but I can't say for sure which ones would keep it.   Were you Edinburgh?  Cos I know this place does - they're the importer and probably supply all the other merchants who might have it.

If you want to be really mean, check on the ground around the edge of the property for fallen gravel.  If there's any sort of quantity, it could be picked up, sorted and washed.  Time consuming, but maybe faster than going to a merchant and back.

https://east-mains-industrial-estate.cylex-uk.co.uk/company/rowebb-specialist-render-centre-broxburn-19574035.html

 

 

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