(Part 1 of this article can be viewed HERE)
Now that we know what causes brickwork to need re-pointing and how to prepare for it, it's time to look at the procedure itself for getting your brickwork back up to scratch!
You will require a hawk to carry the mortar, a pointing trowel and a soft brush
- Always start at the top of the walling to be pointed and work downwards to prevent dropped mortar marking the cleaned brickwork below.
- Make sure the joints are clear of any loose old mortar.
- Load the hawk with mortar flattened to about a 10mm thickness.
- Using your pointing trowel, pick up small amounts of mortar from the hawk and press firmly into the “perp” joints, (these are the vertical joints). Carefully fill each perp joint using a second filling if necessary.
- After filling the perp joints start on the bed joints (these are the horizontal joints)
- Carefully fill each bed joint with a second application if required.
- After completing an area of approximately one square meter, finish the mortar off with a pointing trowel. **
- Apply the mortar filling to the rest of the wall.
- When sufficiently dry, brush off with a fine brush to remove any excess mortar.
** At this stage there are a number of different finishes you could apply, however they require in-depth tutorial that can't be provided from this blog alone. If you would like to find out more, give Access Training a call on 0800 345 7492 for information on our range of bricklaying and construction courses for DIY enthusiasts and professionals alike.
- Richard James
The most common part of a building that usually requires new pointing after it’s been built is the chimney stack. Due to the adverse conditions put upon it, it’s not surprising that it requires re- pointing. Usually you will find that the old cement/mortar will come out fairly easy. A cavity wall tie is often used for this process when the bricks are hard, as no damage will occur to the arris (edge) of the brick. If the bricks are of a soft nature you could use a piece of wood cut down to the width of the joint. Failing this you could use a “plugging chisel” which is a tapered chisel and can be purchased from most building supplies.
Take out all the mortar/cement to a depth of no more than 15mm, ensuring you are wearing the appropriate P.P.E. (safety glasses. dust mask etc.) After all the mortar/cement has been taken out brush all the joints to make sure any loose material is removed. This also make sure the arrises are clean. Do not use a wire brush as this will damage the brick. Wash down the wall with clean water - stubborn patches or stains can be removed using a scrubbing brush. Allow the wall to dry out, if you don’t it will become difficult to point the wall and the bricks may get soiled with the mortar. Also the more water there is in the wall, the more shrinkage movement there may be when the wall dries out. If this happens (moisture trapped in the joints), the first sign of frost the moisture will freeze and will expand and the wall gets damaged.
MORTARS FOR POINTING
If the area to be pointed is built with hard bricks in exposed places, a mix of 2:1 is preferred. This is two parts sand to one part cement, not mixed to wet. For general brickwork a mix of 3:1 is preferred.
In Part 2 I will explain the procedure to carry out the pointing sequence.
- Richard James
If you would like to learn more about bricklaying or any of aspect of the construction trade, Access Training offer a wide variety of construction courses to both beginners and existing tradesmen in need of new/updated qualifications. If you would like to find out more upon what's on offer, give us a call on 0800 345 7492 and arrange a visit of our accredited training centre.
At Access Training our bricklayer courses will train you up to the highest possible standard. However there have probably been instances where you've seen newly built houses or walls with high quality brickwork, only to see white patches unevenly spread over the structure. This is most probably "efflorescence" and this post aims to teach how you can help prevent it in your future work.
So what is efflorescence? It is the formation of (usually white) salt deposits on the surface of brickwork, which causes a change in appearance. Apart from the unsightly appearance and discolouration, efflorescence can sometimes indicate serious structural weakness.
While there is an agreement that it is caused by a multiple of factors being combined with materials, views differ as to which factor is the main cause of efflorescence. It is usually impossible to deduce the exact causes with absolute certainty.
To help prevent efflorescence, some factors to consider are;
Cement: The type/make of cement chosen can influence efflorescence in exceptional cases. Pigments in coloured cement and other admixtures added to the mortar may contribute to efflorescence through their salt content.
Aggregates: These can contribute to efflorescence if they contain soluble salts. Sand contaminated with salt is a major factor, therefore sands in close proximity to the sea are an obvious risk.
Salts: Soluble salt is present in the materials used to make bricks, therefore it is capable of being transported and deposited on the surface as efflorescence.
Water/Cement ratio: Generally a high water-cement ratio encourages the movement of water and salt through the brick, giving rise to efflorescence.
Mortar Constituents: The composition of mortar is of significance. Lime used should be hydrated and free from calcium sulphate. The use of unwashed sand or sand contaminated with salt, or pigments containing soluble salts can also contribute to efflorescence in brickwork.
The following practices may also cause efflorescence;
- No protection from the rain, especially during construction.
- Materials left uncovered on site.
- Lack of drips on cills.
- Poorly filled joints/bad workmanship.
Look forward to future articles which will cover other types of staining to brickwork - including lime staining, vanadium and peacocking.
If you are interested in learning more about bricklaying and would like to train professionally, Access Training have a variety of professional bricklaying courses available. Learn more by calling 0800 345 7492.
- Richard James