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Render is a fantastic way to create a smooth or textured surface to old masonry work. External rendering is suited to many garden styles including modern and traditional design. However, render is not without its drawbacks and it is sometimes common for external render to flake off. There are many reasons why garden wall render can fail including trapped moisture and frost action. In this article I will explain how to remove old render, repair and re-render a garden wall. Can you patch up render on a garden wall?
If you’re render is falling off your wall it is very possible you will be able to patch it up. Firstly, you will have to assess the condition of the existing or remaining render. If it sounds hollow when tapped or easily flakes from the wall then it will need to be removed. If most of the remaining render feels strong and robust you can patch up the garden wall with render. Why is render falling off my garden wall?
Normally rendering falls off a garden wall due to freeze and thaw action. This is where moisture between the render and the wall freezes and expands. The process slowly prizes the render away from the walls surface. This is more typical in low garden walls where there is no damp proof course. Retaining garden walls holding back large volumes of moist soil can also suffer from such action. However, there may be other reasons why mortar is falling of a garden wall.
Sometimes brickwork underneath render can slowly start to degrade. When clay bricks become old and wet they can crumble.
This can make render attached to the bricks also flake and fall. Examine the condition of the structural wall underneath the render to see if is crumbly or powdery. It is also the case that when render is applied it can sump and form air pockets if overworked. If render is towelled about too much on the walls surface it can loose its suction bond while setting. Can you repair render yourself?
As complicated as it sounds and seems you can repair render yourself. If you are a complete novice, the smaller the repair area the better! There is nothing wrong with having a go and familiarising yourself with the process. Most of the time you will need to apply a scratch coat first. This can be a good opportunity to practice towelling and finishing. What is the best sand for rendering a garden wall?
The best sand for rendering has consistent, course and circular particles with no large grit or fine silts. Soft powdery sand like 'brick laying sand' can lead to excess moisture absorption and shrinkage leading to cracks. However, gritty sands like sharp sand can contain larger grit particles which can hinder tight towelling and suction. This is why Leighton Buzzard sand is one of the best sands for rendering as it has uniform and circular particles. For the finishing coat a little builder’s, soft sand can be added to reach a smoother, plaster like finish. Do you need to add PVA to a rendering mix?
PVA has traditionally been added to walls before rendering and the rendering mix itself. It is said that PVA will help the mortar bond better and help to waterproof the render. However some tradesmen say PVA is not necessary and can reduce renders ability to stick. Whatever the case it is advised that you add some sort of mortar water proofer to your rendering mix. This will minimise exposure to damp and frost damage and help the render to bond. What is the best mortar mix for outside rendering?
For the first coat or 'scratch coat' 4 parts plastering sand or sharp sand to one part cement. For the finishing coat I mix 4 parts plastering sand 1 part builder’s sand and 1 part cement. You could also use hydrated lime instead of the builder’s sand. Make sure you add plasticiser to make your mix more workable. You can also add water proof admixtures to prevent moisture and frost action. How thick should render be on a garden wall?
Typically about 12 mm is about right for an external rendered garden wall. Don’t forget you will first need to apply a scratch coat of about 5mm. Then you can apply your finishing coat of about 7mm. Why is render not sticking to my wall?
Render may not be sticking to your wall for a number of reasons. The most common reason is fine traces of dust and dirt are preventing render bonding to the wall. To mitigate this, make sure you brush and wash your wall done thoroughly first. During warm and dry weather absorbent walls can suck out renders moisture quickly. This can result in a loss of suction and the render failing to stick to the wall. Trying to apply too much thickness in one go can lead to render simply falling off the wall. How to repair rendering and render a garden wall step by step.
Step 1.
Investigate the existing rendering to see how loose it is and remove any flaking mortar.
Step 2.
Examine the wall further by tapping the surrounding mortar with a bolster. Weak and unbonded render will sound hollow compared to solid areas.
Step 3.
When you have identified hollow render, using a hammer and bolster remove it from the walls surface. You should only really leave render which is solid and cannot be separated from the wall.
Step 4.
Using a wire brush, brush off any weak rendering or flaking paint from the walls surface. Make sure you wire brush the walls surface to remove any degraded or loose materials.
Step 5.
Using a hand grinder, score grooves into the surface of the wall to provide a key for new render. This is not always essential but provides extra grip if you want the strongest result. Make sure you wear a tightly fitted dust mast and eye protection!
Step 6.
Your cutting will create lots of fine dust, consequently when finished you must clean the wall thoroughly. This is best achieved with a bucket of water and a hand brush. Make sure you brush out all the dust residues from the surface and cut scores. You must then allow the wall to dry out.
Step 7.
Empty two golf ball sized blobs of external, waterproofing PVA into the bottom of a bucket. Fill the bucket two thirds full with water mixing in the PVA until it dissolves.
Step 8.
Using a hand bush, coat the wall with the PVA solution. This will help the mortar to bond better to the wall below. It is also beneficial to have the wall ever so slightly damp on the surface before applying render.
Step 9.
Mix up your first render coat, I typically use 4 parts plastering sand and 1 part cement. I add about two egg cups of both mortar plasticiser and waterproof PVA to the mix. Mix until it has a stiff but workable consistency.
Step 10.Using a brick laying trowel, load up your rendering trowel with a wide load of render. Start at the base of the wall tilting your wrist so the render gently makes contact. Using a steady movement, glide your hand up vertically forcing a layer of mortar up onto the wall. This will take a little practice to get a feel for how much pressure to apply. Make the render as smooth and as a consistent depth as possible. Step 11.
Use this first scratch coat as your practice run for applying the finished, smooth surface! You can use a straight edge to gently screed off high points.
Keep working render into the low points until you have a relatively level surface. When the mortar is starting to go off, score some key lines into the surface. This is the reason for the first coat being called the scratch coat. Allow this at least 24 hours to set before applying the finishing coat. Step 12.
Mix up the final coat, This can be slightly weaker than the base scratch coat. I prefer to mix 4 parts plastering sand, 1 part soft sand and 1 part cement. As before, I like to also add plasticiser and PVA External water proofer. Mix until you reach a moist and workable consistency. Step 13.Using your rendering trowel apply the render to the wall as evenly and smoothly as you can. Try to keep an even and consistent thickness as this will help the mortar to stick well. You can use a straight edge to gently screed off high areas. As the render starts to dry you can fill in low spots gently. Try not to over work the render as this can lead to air pockets forming and it falling off. Rendering is a bit of a skilled art and will take some time to master.
When you have the render as smooth and consistent as possible you can have a rest.
You now have to wait until the face of the render starts to become firm. How long this takes will depend upon the temperature, time of year and the moisture content of the wall. You will have to keep an eye on each section as it can set inconsistently across the walls surface. Step 14.
Using a sponge float, or damp sponge, start to softly work the surface of the render in circles. This will slowly open up the surface of the mortar and allow the render to breathe. Gently working the renders surface will allow any small blemishes to be evened out. This gentle process will also allow low spots or hollows to be gradually filled in.
Step 15.
You have now completed your rendered wall and can be pleased with your work of art! Do leave your render at least a couple of weeks to set before painting.
Thank you for reading our article on how to repair rendering and render a garden wall. We have featured some other articles below you may find interesting.
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It is very common today to look at concrete paths as old and outdated. However, concrete is still one of the most affordable and versatile building materials.
Concrete paths can be moulded into any form or shape including curves and angles. They also do not have to be visually boring as they can be worked into a wide variety of finishes and textures. Other products such as resin bound aggregates and addagrip can also be applied to the concrete paths surface. There are also a variety of dyes, moulds and paints which can alter and adapt the aesthetic qualities of a concrete path. In this article I will show you how to make a garden path with concrete step by step. Can you lay concrete on soil?
Concrete has a very high compressive strength; however it has a very low tensile capability. Any movement can induce cracking and failure. Therefore, it is important that concrete is laid on a solid base of compacted hardcore. This means you will have to excavate out any soft and loose topsoil before laying concrete. Ideally you will need to dig down to a more rigid and robust sub soil. The depth of the excavation will vary depending on your local soil type. However, generally, a depth of around 170mm is normally sufficient. How deep should a concrete garden path be?
Between 4 and 6 inches is about the correct depth of concrete for a path. In metric that is a range between 100 and 150mm. Although in reality the deeper the concrete the better as there is less chance of movement and cracking. I would say 5 inches or 125mm is a good depth of concrete for a garden path. Do you need an expansion joint in a garden path?
For most concrete garden paths you should be able to avoid an expansion joint. However you will need to incorporate metal reinforcing rods or mesh into the concrete. Once a garden path goes beyond 10 metres having some sort of expansion joint becomes inevitable. If you have very stable subsoil and lay at a generous depth you may be ok for a greater distance. My advice is if you really can’t stand the idea of a joint lay the concrete without one.
If then it does crack you can cut out a small section later and add one then. Just note if you choose this rout you may not get a consistent colour and finish with newly laid materials.
On the whole the longer distance you wish to go without an expansion joint the thicker and more reinforced your concrete should be. However, I would recommend a joint every 10 metres at most. Expansion joints can be formed with thin ply board or other external grade and rigid, sheet, material. How to make a curvy garden path with concrete?
The great thing about concrete is it can be formed into pretty much any shape. However it will take skilled labour to instate the formwork correctly. In order to make a curvy, garden path, you will need flexible retaining edgings. The most common materials for these are stainless steel edging and thin timber gravel boards. All curved edgings must be flexible but also robust enough to take the weight of wet concrete. This can be achieved by driving in timber stakes in and around the boards with a sledge hammer. Boards can then be fixed using external grade screws and a power drill. Other flexible edgings can be haunched into position with strong mortar mixes. The wet concrete can then be tamped level with the top of the edgings and towelled smooth. How to make a garden path with concrete step by step
Step 1. Plan the shape, direction and route of your path making sure it is both functional and aesthetic.
Step 2. excavate out any soft soil where the new concrete path is to be situated. This is typically at a depth of about 170mm.
Step 3. Using a string line tightly plot out and realise your finished level. This could be from the level of a back garden shed base to a patio.
Step 4. Using 50mm x 50mm timber pegs peg out to the top of the string line using a sledge hammer. This will enable you see your completed level and mark your concrete and hardcore levels on the timber.
Step 5. Using a pencil or pen, mark your hardcore level onto the pegs. If you are laying 5 inches of concrete the hardcore level will be 5 inches below the top of the peg.
Step 6. install your retaining formwork or edgings these typically consist of timber boards or an edging of some kind. Your formwork or edging level must be consistently flush with the string line or the top of the pegs. This will allow for a consistent gradient with no risk of puddles.
Step 7. Secure your edgings robustly so they can retain the weight of wet concrete. This could be with mortar haunching but also with timber pegs and 6x2 timber like in the example below.
Step 8. apply pressure to your formwork to make sure it doesn’t move under stress. Timber boards can be reinforced and fixed with more pegs and external grade screws.
Step 9. Fill your formwork with a base of compacted hardcore and compact. This helps the ground beneath to bond well to the concrete. Here you can spread old masonry materials like bricks and concrete as long as they are well broken up. However, the best material for this is mot type 1 compactable hardcore.
Step 10. Install reinforcing if necessary, this can be done with metal, reinforcing mesh or any ridgid wire mesh. In the example below I used an old waste egloo chicken run wire mesh. Try to elevate you mesh up so it sits within the centre of the concrete.
Step 11. work out how much concrete you need. For this you will have to measure the surface area and times it by the depth.
Make sure you get the decimal point in the correct place! There are online calculators which can do the calculation for you. However, for example, if you have a path which is 1 metre wide and 10 metres long that will be 10 square metres. If you’re concrete depth is 5 inches or 125mm the calculation is: 10 X 0.125 = 1.25 This means you will need 1.25 cubic metres of concrete for the concrete path. A cubic metre is about two jumbo bags. Bear in mind you should always get a little bit more than what you need to do the job to avoid running out. Therefore you will need about 3 bulk or jumbo bags of ballast to do the concreting. I always allow 6no 25kg of cement for every jumbo bag so you will need 18 bags of cement.
Step 12. Mix your concrete, to get a ratio of 5 parts ballast to 1 part cement, mix half a bag of cement 12.5 kg to about 12 shovels of ballast.
Put two thirds of a bucket of water into the cement mixer and turn it on. Add half a bag of cement and let it turn until all the clods have become soluble with water. Shovel in the sand gradually so it mixes well and allow mixing for at least 1 minute. Your concrete should have the consistency of porridge. It should not be too wet that it runs like water and stiff enough to work with some water on the surface.
Step 13. Pour your concrete into a wheelbarrow and tip it into your formwork. Using a rake, spade and trowel move about the concrete until it is slightly above your retaining edgings and formwork.
Step 14. tamping. Using a clean straight edge like a piece of timber or long spirit level, start to tamp the top of the concrete.
This will work the wet cement or ‘cream’ to the top and allow you to work a consistent and smooth finish. You may need to drag back some concrete as you work so your finished level is not above your edgings. This takes some practice but is quite fun and you will enjoy the process ‘very satisfying’.
Step 15. Finishing. To get a consistent finish to the concrete vibrate and bounce your straight edge over the surface. As the concrete bounces angular particles will shuffle and become densely packed. This will make the strong cement cream come to the surface making it easy to work to a smooth finish.
Step 16. Curing. Make sure that nothing disturbs the concrete once you have a good finish. Cats should be kept inside for a few hours and make sure there is no rain in the forecast for at least 12 hours. Make sure all tools and edgings are clean of excess concrete so they do not stain.
Please note.
If you are concreting a garden path in summer make sure the concrete does not dry out too quickly. This can lead to improper curing and a weak, crumbly concrete. If you have to concrete in such conditions lay plastic under your path and make your mix slightly wetter. This will prevent moisture being drawn out too quickly disrupting the curing process.
Thank you for reading our article on how to make a garden path with concrete. How did you concrete path project go? Please feel free to comment below or email me questions regarding your particular project.
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Gravel is one of the most diverse and versatile of all the garden surfacing materials. It comes in a wide variety of size grades, materials and colours. This makes it able to fit in with pretty much any garden style or theme. From contemporary and modern show gardens to rustic Tuscan courtyards, gravels aesthetic is universal. Not only is gravel visually effective it is also very affordable! Buying gravel and spreading at 40mm is five times cheaper per metre than buying new paving. Add to this the beneficial fact that gravel is also about 5 times faster to lay!
With no need for highly skilled labour, gravel can be laid by anyone well!
From a sustainability aspect gravel also scores well! Contextual aggregates can be sourced from local quarries reducing a gardens carbon footprint. Furthermore, lose gravels are permeable allowing storm water to pass straight through. This helps to reduce flash flooding and protect local watercourses. So, now you’re excited about gravel, I will show you how to make a gravel path! Can you lay a gravel path straight onto soil?
A gravel path really needs a sub base to stabilise the underlying ground. Gravel laid directly on to topsoil will eventually sink into the soft ground below. This means you will end up with a compacted and boggy mess full of weeds. Do I need to dig before laying gravel?
Ideally you should dig out a gravel path to a depth of 140mm. This will allow 100mm for a compactable hardcore aggregate such as type 1. It will also allow a 40mm depth of gravel. How deep should my gravel be?
I have found that a depth of around 40 mm is ideal for a gravel path. Too shallow and you will not hide the membrane and have the added risk of weed establishment. However, too deep and you will find the gravel challenging to walk upon. I find a 40mm depth allows enough displacement to kill geminating weeds but is comfortable to walk upon. What should I put under a gravel path?
A gravel path should have about 100mm of compacted sub base aggregate for pedestrian traffic. The most effective and widely available is mot type 1, available from most builders merchants. On top of that you should lay a robust, landscape grade, membrane. This is to discourage weed establishment and gravel mixing with the sub base layer.
Should I put landscape fabric under a gravel path?
Often you see people putting landscape fabric at the bottom of a paths excavation. I think due to the fact many people assume weeds grow up through paths. Except for a few robust and woody perennials on the whole this is not true. If you excavate down 140mm you will be able to remove all threats of weeds growing under your path. Combined with at least 100mm of well compacted sub base your path will not be suitable for weed growth. Weeds more typically seed in the damp edges of shallow gravel. This is why I advise to lay your fabric on top of your sub base and under your gravel. How do you keep gravel on the path?
The best way to keep gravel on a path is by having suitable retaining edgings. Normally the wider and more stable the edgings the less gravel will escape. It is also important not to spread the gravel too deeply. This will encourage accidental kicking and scuffing of the aggregate as people walk. Sometimes the secret to keeping gravel on the path is the size of the aggregate. Very small aggregates are easy to pick up in the treads of shoes and easier to kick around. How to make a curvy gravel path?
To make a curvy path you will either; need to install flexible edgings or lay masonry edgings. These will allow you to shape the outline of your path with curves. The most typical flexible edgings are steel edgings like Everedge or long gravel boards. These can be fixed into position with pegs and mortar. Using small masonry units such as bricks, sets and blocks also allow you to form curved edging easily. When designing the curvy shape you can set your path out with hose pipe. This will enable you to visualise its shape before committing. The curvy shaped path can then be sprayed out or pegged. Do gravel paths need edging?
Gravel paths do really need some form of retaining edging to contain the aggregate. If you do not install edgings soil and dirt will infiltrate your gravel. This will lead to mud and silt filling up the aggregate and weeds becoming established.
How to make a gravel path step by stepStep 1.
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