Average Labour Cost/Price of Rendering/Pebble dashing (Pebbledashing)





To clarify the following prices it is recommended that you read the article in the INFORMATION box below the PRICES…


(These prices are based on a tradesman’s rate of £150.00 per day and a labourer if required at £100.00 per day. This includes the cost of buying and collecting any materials, dumping any waste if necessary and any incidental materials they will need. The minimum price will usually be for a half day)



How Much Does it Cost To Render Walls?


walls render


Job 1
You want all the 3 walls of your semi, rendered. This will require scaffolding and it will take 3 men 7 days (2 spreads and 1 labourer). This is to prepare the walls properly by belting out all the mortar joints, do the job with proper waterproofer and clear up.

The scaffolding will cost £750, materials £425, the labour £3000 £4175.00.

Job 2
Same job but with pebbledash

This will be more expensive purely because of the cost of the “dash”. The labour is about the same.
£4400.00

Job 3
The render, either dashed or otherwise is “blown” (has become loose) and is actually coming off on one badly weathered wall of your house and you want it repaired.

Do you really want to end up with a patchwork quilt? Because that’s what you’ll get! With the best will in the world no builder can do invisible mending, every bit he repairs will show. Bite the bullet and do the whole wall.

This will take three men 3.5 days, not
all the stuff will want to come off the wall, so it will have to be belted off with mechanical hammers.


Scaffolding £350, materials £245, Labour 1470
£2100

To add pebbledash instead of smoothing the final coat £50.00
Job 4
You want the 3 sides of your single storey brick extension prepared properly then rendered. We will assume there is one patio door and one other window/door. Render stop beading will be fixed horizontally just above the damp proof course.

This will take or three brave soldiers 3.5 days and will not require scaffolding.

£1650.00

The same job if you have prepared the walls properly yourself will cost £1230.00







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A Price Guide and Information Sheet on Rendering and Pebbledashing



information


Rendering

Rendering is effectively spreading mortar all over the brickwork and leaving it flat and “smooth”, with nice sharp corners and edges, usually formed using metal beading.

Walls are rendered for two reasons. Wattle walls were rendered originally (1000 years ago) with “daub” (don’t ask), out of the usual desire to keep out rain. This progressed as a
sort of necessity, when weak, hand-made bricks took over that still needed a bit of assistance, repellent wise. This carried on until the early 1900’s.

Now, new houses (and extensions) are rendered (sometimes just in certain wall areas), because of tradition, or because
block work, not brickwork, has been used. Existing houses are rendered because the bricks are horrible or “spalled” (exfoliated) or are letting water in. (nothing changes then).

Pebbledash is just a decorative effect added to the last coat of render since the 1930’s, that seems to go very well with net curtains!

The original rendering mortars (after daub) were mostly sand and lime, then sand cement and lime and now, unless it’s a specialist job on stone for instance, just sand and cement.

Ideally the “muck” (builder’s parlance for mortar) goes on the wall in three coats. Traditionally these are called the render, float and set. The strength of each coat (the ratio of sand to cement powder and lime if its used), is very important and will vary dependant on the type of brick or stone it’s being applied to. Too strong a mix for the background will result in cracking for instance.

Firstly and vital to all renders, the brick or stone or cobb or whatever forms the surface of the wall being rendered,
must be seriously roughed up (or keyed) before the spreading begins. (“Spreads” as well as other choice little phrases, are what builders call the plasterers. Plasterers do the outside rendering as well as the inside plastering).

This keying usually means knocking out the pointing or even taking an angle grinder to the wall and scoring it hundreds of times, (that’s a job for the hard men).
If the wall isn’t properly keyed the render WILL fall off!

The “render” coat will be the thickest and strongest of the three and will be “scratched” with lots of deep lines. This gives a good key for the next coat and also provides stress relief lines during drying. In other words it’s allowed to crack where the plasterer wants it to, as it shrinks. If it cracks of its own accord, it will loose adhesion. This coat is the one which is “screeded” as necessary to remove the wall’s anomalies and get it flat. (Screeding is dragging a long metal blade called a “derby” over it, though a straight piece of wood will do).

The “float” coat is put on next, this will be a
bit thinner and weaker and it too will be scratched. Lastly the “set” coat is applied. This is the one which shows and should be left flat and “smooth”. Several things can spoil the finish including over trowelling or laying it on in very hot weather where it dries too quickly.

Actually using a large sponge
at the right moment in a circular motion, will produce a pleasing sandy finish.

The art of any form of plastering is knowing when to leave it alone and stop playing with it! Timing is everything, this depends on ambient temperature, how long it has been on the wall, how dry the previous coat was, what was in or on the previous coat and what’s in the set coat.

Today, render is mostly put on in 2 coats. If they’re thick enough, scratched properly, are the correct strength and have the right things in them, that’s good enough. Too thin and amazingly all the mortar lines (beds) in the brick or block work underneath will show through. This is called “grinning”.

No experienced plasterer will even
think about rendering in just one coat! It will always make a complete fool of him and the wonderful phrase, “one coat billy goat” will follow him wherever he goes. How do plasterers all know this? Because every single one of them has tried to get away with one coat at some time in the past. It seems so simple you see, “If I really concentrate and put some PVA in the mix…”

The type of sand used is also very important. Builders use three types, “soft” or “builders” sand used for bricklaying, “sharp” used for floor slabs or screeds, and the type they must use for rendering which is called “washed, fine washed or just plastering sand”. It tends to have larger grains than soft sand but it’s the washed bit that’s most important. Its been washed to remove all the sulphates and other salt impurities out, which would eventually ruin the render.


Things to put in or on the wall, or each coat.


PVA adhesive, (no we don’t know what it stands for, we’re not rocket scientists)!

This can be diluted quite a lot and toshed onto the wall (more parlance I’m afraid) to seal all the dust. Then just before laying the muck on, a much stronger dilution can be brushed on, left to go tacky and then rendered over. This will seriously help stick the muck to the wall.

PVA is also used on very porous surfaces such as aerated blocks and old bricks to slow down their suction effect. Mortar both sets and bonds to walls, because of a chemical reaction called hydration, (maybe we
are rocket scientists) Water is vital to this process. If a base material is too dry and sucks the water out of the mix too quickly, this chemical process is messed up, the cement and sand don’t bond and it all falls off.


Waterproofing Agent,


This is a brilliant modern invention and it actually, (after 500 years of trying), makes the render waterproof! It goes into the base coat and because it won’t let water in, an added advantage in hot weather is to slow down the setting process and stop accelerated drying and subsequent cracking. It is also added to the finish coat to really waterproof the stuff and give the “spreads” more time to get the finish right.

Don’t skimp on the waterproofer. Good ones (like “Sikka”) are expensive (£35 for 5 litres). Cheap ones (£10 for 5 litres) are about as much use as a chocolate fireguard.

Air Entraining Agents,

These, as the name suggests (if you happen to be emeritus professor of advanced gobbledegook at Oxford) coax lots of air into the muck as its being mixed. Air makes it lighter and easier to trowel on the wall. These (if the builder can read the label and use them properly) also aid the render’s long-term performance.

Pebbledashing


Dashing…….It’s a bit of an art. It’s very easy to get it horribly wrong as well, so make sure your chap knows what he’s doing. There’s various types and colours of pebble so have a look around and see which you like best. He will probably mix lime with the final mortar coat, this traps a lot of air, makes it lovely and light and better still, lovely and sticky.

It needs to be both sticky and just thick enough to hold the pebble you have chosen. Too thick and the pebble can disappear, too thin and it will hit the coat underneath and bounce off.

As with “smooth” rendering, where he makes any joint, if he has to come back next day is just as important. They will show just as much with pebbledash.

SO

Lets assume your brickwork is exfoliating (it’s called “spalling if you’re a builder), it’s when frost is causing the fronts of the bricks to fall off. So you want the whole wall rendered.


Questions to ask the roofer during his quotation visit.



(Working from the wall outwards)

Will you first prepare the bricks by removing all the existing loose bits?


Will you rake out the pointing to about ½” (12mm) to provide a key for the render?


Will you prime (and seal) the brickwork with dilute PVA?


Will you then apply stronger PVA just before applying the first coat?


What type of sand will you be using?


How will you be forming corners and window and door reveals?
Really they should make rounded corners as they go. They could use edging beads but if they do, make sure they’re stainless ones, set in place with their mortar, prior to starting rendering.


What strength will the first coat be?
If the wall is Victorian red or yellow “stock” bricks this should be 4:1. If the wall is 1930’s “common” “facing” bricks, 3:1 is better.


Will you be scratching and waterproofing the first coat?


Will you apply strong PVA just before applying the second coat?
This won’t need sealing, there should be no dust.


What strength will the second coat be?
4:5:1 for the “stocks”.
4:1 for the “commons”


Will you be adding waterproofer to the finish coat?
This will help him after all.


Which waterproofer will you use and how much is a 5 litre tub?


Where will you make the joints between areas of render?
Unless he arrives mob handed, each coat can’t be “laid on”, all round the house in one go. This isn’t important except for the final coat. He will want to work on each “lift” (or level) of scaffolding at a time. This will mean two or three, horizontal layers of render around each wall of the house. No matter how good he is, the joints between these layers will show as soon as the scaffolding comes down, even if its been painted. You will not be happy with this!


What he should do with the final coat is this:
Work in vertical bands (not horizontal ones) and have 1 man per lift “laying on” the final coat. This way they work above and below each other across each wall ignoring the horizontal scaffolding levels, finishing the surface as they go, so they shouldn’t have to go back on themselves. This will always leave any stopping point (when they go home for their teas) as a vertical line.

This is easier to deal with, as its right in front of their face (as opposed to being at the level of their boots, hidden by the scaffold boards). If they have to come back and continue next day and they have stopped behind a down pipe or the toilet waste pipe which are vertical, they can begin again from behind the pipe and the joint will be hidden.

What they must not do is stop at the point of a corner. Future wall movement will exacerbate any potential cracking here. If they can’t stop at a pipe, then the short bit of vertical wall between first and ground floor windows can be used.


How will you finish the surface, trowelled smooth or “sponged”?
Both are fine, both can be painted.


Will you take the time to clear up properly?
Getting the slopped PVA off the window frames and glass. The dust (from knocking out the pointing) off your’s and your neighbour’s paths and windows and cars. The dropped mortar off your paths and garden. The incidental mortar off your window frames, porch roof, down pipes, garden furniture, etc. The stains off your patio where they mixed up the mortar……… HAVE YOU GOT THE MESSAGE ? And the scaffolders haven’t wreaked havoc taking that down yet!





A-Z of Job Pricing