They say the three most important things about buying a house are Location, Location and Location. Well the three most important things about keeping your house warm are Insulation, Insulation and Insulation (although I guess you need a boiler too!).
I was doing some more insulation yesterday, I put glass wool between the joists on my ground floor. Why? Well I have a vaulted floor with about 450mm of space below it, and this space, as with all houses, is vented to the outside via some vent bricks to allow air to flow and to keep the space dry. Well at the moment I don't have carpet down so two things happened when it was cold or windy. Firstly, you get drafts coming through any gaps in the floorboards (the boards are tongue-and-groove but there are still spaces in some places). The other is simply that heat from the living room is conducted downwards into the cold void. Even carpet does not insulate that well, although it can reduce drafts, otherwise we would just use carpet to insulate our lofts.
To fill the cavities, I made a hole in the floor and crawled under the void. I pushed the glass wool into the gaps and then covered the underside with a large tarpaulin which I nailed into the joists to hold the glass wool in place. Note that my floor joists are only 100mm because they are supported by a small wall in the middle and I assumed that they would be 200mm because they were floor joists so I had to cram the glass wool in a bit. Better check the size and get the correct insulation because if you crush too much air out of the wool, it doesn't insulate as well.
Another area I insulated was the floor void between ground and first floor, particularly the part next to the outside wall where it is common to have gaps between the inside of the void and the external wall cavity - another place for drafts and cold. I stuffed some more glass wool into these gaps and it should make a bit of difference.
I also bought a couple of curtains to cover my front and back doors which although U-PVC do leak drafts around the edge. The curtains help to remove the drafts and slow convection of the warm air inside the house onto the door which then conducts outside.
Once the loft is insulated, none of these other fixes make a big difference by themselves but once added up, they do make a noticeable difference.
Showing posts with label diy. Show all posts
Showing posts with label diy. Show all posts
Wednesday, 29 December 2010
Friday, 13 March 2009
Between the floors!
Have you ever thought about what is between your floors when you are doing building work? They are very important spaces so here is some wisdom:
- Do not leave wood shavings in the gaps when you drill joists and floorboards, think how well that would go up in flames if you had a fire or electrical fault! Vacuum is your friend.
- If you drill significant holes into a plaster ceiling, you have compromised its fire stopping ability and the building regs say you need to mitigate this. If you drill downlighters into the ceiling, either you must use the closed back ones which block fire (and cost more!) or put in a false ceiling to drill into or use a fire blocking device above the downlighter to prevent any compromise of the ceiling due to a fire.
- If you can, fill the spaces with 'rockwool' type insulation which helps keep noises to a minimum, provides heat insulation so that warmer rooms are not heating up cooler rooms unintentionally and also it reduces the effects of drafts on potential fires - floor voids are wonderful places for fires because there are often drafts from leaky brickwork which if left un checked would feed a fire.
- Make sure you know what you are allowed to do when notching or drilling joists for pipe and cables. You are not allowed to drill too large or too close together so find out from the building regulations guidelines. You do not want a joist to give way, especially one under a water tank, wall or bath which would go very quickly.
- If you are pulling in cables or flexible pipes, invest in some fibre-glass pull rods. You can pull through voids that are perhaps 20 feet or more long without having to pull up any floorboards in the process.
- If you drill outside from a floor void, close the gap afterwards with fire-rated expanding foam both to reduce chills from drafts, prevent vermin getting in and also reduce the effects of fire.
- Watch out for noggins. They are (usually) blocks of wood which cross the void in an X shape and are to stop the joists twisting under load and over time. They can be a pain when pulling cables and pipes through. If you can raise an odd floorboard, do it near the noggins. Try and consider avoiding airlocks as well by passing water pipes under the noggins rather than over them (like I did!)
Wednesday, 10 September 2008
Eco-Friendly House DIY Style
I moved into a new house about 3 months ago. Well, it's not quite new, more like 70 years old but it's new to me. Because I have a bit of money, I wondered what to do in my new house. I came up with two things. I wanted it to be eco-friendly and I wanted it to be one of these automatic houses. More on the auto thing later but first eco-friendly is not a term I particularly like because it conjures up images of hippies and dirty people who would be more attractive if they washed and did their hair! I don't care for some of the so-called eco-lifestyle such as all sleeping in the same bed to share warmth and eating mouldy vegetables from the garden but there are good things about it too. Forget the fact that I would save umpteen tonnes of CO2 because I don't really know how much that is but saving CO2 also means saving money and this is also a good reason to make your house friendly to the environment.
Anyway, there are some things that make a big difference and some that don't. Search the web and there's loads of stuff about all things eco.
I want to share my investigations about insulation since it is the easiest thing to do to make your house use less fuel to heat it. Most people have heard about 'fibre-glass' loft insulation but there are some things you might not know. Currently the Building regulations recommend a minimum of 250mm of fibre-glass type loft insulation. That usually equates to 100mm between the ceiling joists and another wider strip of 150mm going across the first strips to add extra warmth and cover the gaps left between the joists and the 100mm insulation. Find out how much you have in your loft. If only a little bit is there, add some more or replace it. It might cost about £200 but it will not only feel warmer but will reduce your heating bill (as long as you have a thermostat in a useful place or thermostatic radiator valves (TRVs)). Whatever you do, don't open the windows to compensate for the extra warmth. Fit TRVs which will turn the radiator off when the room gets warm. If you are going to convert the loft into a usable room then keep 100 or 150mm insulation in the floor (to stop all the downstairs heat making its way to the loft) but you will also have to add insulation to the rafters. Unfortunately, the rafters are unlikely to be much taller than 100mm (4 inch) which is not deep enough for fibre-glass to provide good insulation so you will have to use rigid phenolic or similar insulation (often called Kingspan but available from other places too). This is quite expensive, about £35 for a 2.5 x 1.25 metre slab at 70mm but it is much higher spec for the size. It can be quite tricky to fit because every gap between the rafters will be a slightly different width and if there are gaps between the side of the slab and the rafters, then the insulation properties will be a bit rubbish. You need to measure each gap and I would suggest doing a section no longer than 1.25m/4 feet at a time otherwise it is a pain. You need to do something to ensure an air gap above the insulation to avoid damp problems unless you have breathable felt in which case you don't. Breathable felt is more like soft fabric whereas tar-type felts do not breathe.
Once your roof is insulated, if you picture the heat inside the house it will rise towards the top ceiling and then move sideways towards the walls. If the walls are not insulated then you could lose a great deal of heat, especially in the winter when prolonged cold causes the walls to absorb lots of heat from inside. If you have a cavity wall (most houses since the 1970s) then arrange to get it filled with insulation. Phone around for prices since some systems are very expensive. If it is already filled (most houses since the 90s) then you will not gain much by doing anything else but if, like me, your walls are solid brick or concrete then you would do well to insulate them. You can do it externally with a render type product (or rather somebody would do it for you) or you can go a much easier route and batten the inside of the walls with 2 x 1 inch wood and fill the gaps in between with 25mm solid insulation (about £10 per sheet) then cover the whole lot with plasterboard, screwed to the battens and tape/plaster it and hey presto - not bad wall insulation. If anything, it protects the cold surfaces of the walls directly touching your nice heated room and stealing all your heat. Since the inside surfaces of walls do not generally get really cold, the insulation will work just fine.
Now double-glazed windows are amazingly expensive, especially when you look at how quickly they are manufactured. For this reason, there is not much point in replacing your windows unless they are broken. It can take 25 or more years to re-coup the cost of the windows and they might not even last that long and that is compared with single glazing rather than existing double-glazing.
There is one reason why eco is good and that is because fuel costs go up and up all the time. In the future, suppose electricity costs a £1 per unit, having your lights on would cost enough let alone other utilities. A house that is very efficient will mean that you can afford to run it properly and comfortably. mmm Nice
Anyway, there are some things that make a big difference and some that don't. Search the web and there's loads of stuff about all things eco.
I want to share my investigations about insulation since it is the easiest thing to do to make your house use less fuel to heat it. Most people have heard about 'fibre-glass' loft insulation but there are some things you might not know. Currently the Building regulations recommend a minimum of 250mm of fibre-glass type loft insulation. That usually equates to 100mm between the ceiling joists and another wider strip of 150mm going across the first strips to add extra warmth and cover the gaps left between the joists and the 100mm insulation. Find out how much you have in your loft. If only a little bit is there, add some more or replace it. It might cost about £200 but it will not only feel warmer but will reduce your heating bill (as long as you have a thermostat in a useful place or thermostatic radiator valves (TRVs)). Whatever you do, don't open the windows to compensate for the extra warmth. Fit TRVs which will turn the radiator off when the room gets warm. If you are going to convert the loft into a usable room then keep 100 or 150mm insulation in the floor (to stop all the downstairs heat making its way to the loft) but you will also have to add insulation to the rafters. Unfortunately, the rafters are unlikely to be much taller than 100mm (4 inch) which is not deep enough for fibre-glass to provide good insulation so you will have to use rigid phenolic or similar insulation (often called Kingspan but available from other places too). This is quite expensive, about £35 for a 2.5 x 1.25 metre slab at 70mm but it is much higher spec for the size. It can be quite tricky to fit because every gap between the rafters will be a slightly different width and if there are gaps between the side of the slab and the rafters, then the insulation properties will be a bit rubbish. You need to measure each gap and I would suggest doing a section no longer than 1.25m/4 feet at a time otherwise it is a pain. You need to do something to ensure an air gap above the insulation to avoid damp problems unless you have breathable felt in which case you don't. Breathable felt is more like soft fabric whereas tar-type felts do not breathe.
Once your roof is insulated, if you picture the heat inside the house it will rise towards the top ceiling and then move sideways towards the walls. If the walls are not insulated then you could lose a great deal of heat, especially in the winter when prolonged cold causes the walls to absorb lots of heat from inside. If you have a cavity wall (most houses since the 1970s) then arrange to get it filled with insulation. Phone around for prices since some systems are very expensive. If it is already filled (most houses since the 90s) then you will not gain much by doing anything else but if, like me, your walls are solid brick or concrete then you would do well to insulate them. You can do it externally with a render type product (or rather somebody would do it for you) or you can go a much easier route and batten the inside of the walls with 2 x 1 inch wood and fill the gaps in between with 25mm solid insulation (about £10 per sheet) then cover the whole lot with plasterboard, screwed to the battens and tape/plaster it and hey presto - not bad wall insulation. If anything, it protects the cold surfaces of the walls directly touching your nice heated room and stealing all your heat. Since the inside surfaces of walls do not generally get really cold, the insulation will work just fine.
Now double-glazed windows are amazingly expensive, especially when you look at how quickly they are manufactured. For this reason, there is not much point in replacing your windows unless they are broken. It can take 25 or more years to re-coup the cost of the windows and they might not even last that long and that is compared with single glazing rather than existing double-glazing.
There is one reason why eco is good and that is because fuel costs go up and up all the time. In the future, suppose electricity costs a £1 per unit, having your lights on would cost enough let alone other utilities. A house that is very efficient will mean that you can afford to run it properly and comfortably. mmm Nice
Friday, 29 August 2008
DIY Help - Floor joists in the loft.
It still seems a common but sad fact that most UK houses are built with a mostly useless space in the loft. If you want to use it then you will often have to carry out some often extensive remedial work to either strengthen it for use as a room and/or making space in the roof woodwork for what you want. Ironically, newer houses are worse than older houses in this respect since the newer cheaper to build trussed roofs often leave little or no room to use without major alteration. When you alter these roofs, you end up having to revert the structure back to an 'old fashioned' style with purlins (the lateral large joists that stop the vertical joists from sagging).
Anyway, lots of people ask about strengthening floors in the loft and when this is requried/what size timber etc. The science is quite straight-forward. The joist performs 1 or two functions (usually) the first is to support the imposed load of the room: dead weight is the joists, floorboards, fixings etc and the imposed load is the stuff we have in our rooms, whether people, baths etc. The second function that joists often perform, especially in the loft, is to act as a tie beam for the roof or walls so that the weight of the roof does not cause the bottom of the pitch to spread out (imagine folding a piece of paper in half and putting it on the desk like a tent, what happens when you press down on the top of it?). In downstairs rooms the joists will also stop walls from collapsing inwards which might happen if you took out all your floors without supporting the walls first.
Your first question therefore is what weight or force do the joists have to take in order that they don't sag excessively causing ceilings to crack. This is largely dependent on whether the loft will be used as a room (in which case it is the same as all other rooms) or just for some light storage (in which case if you keep the storage above about 3 feet of the supporting wall in the centre then you would probably get away with the existing joists - the sagging after all is largest in the centre of the joist span.
An Architect or Structural Engineer will be able to tell you what the recommended joist sizes are and these are related to the quality of wood (commonly called C16 - weaker or C24 - stronger) and also to the span that the wood has to bridge. If the walls are 2 metres apart then the wood will sag less than if they are 4 metres apart. Unfortunately now these tables are not publically available and are held by an organisation called TRADA (of which architects etc are members). You might be able to get a friend to look for you or ask at your library. These tables might say for instance that a piece of 50 x 220 timber in C16 quality can span a distance of 4.64 metres (or more likely you will have measured 4.5 metres and found the cheapest and smallest size of timber that meets this span as 50 x 220mm). Nobody is checking mm but don't take any big risks because the few more pounds of larger wood will be less than repairing your plastered ceilings when they crack or fall.
If you are planning to fit the joists yourself then you need to be comfortable working out the loadings of the roof (unless you are simply adding in the joists without touching the existing structure). In most cases, in a purlin'd roof, you will need to move purlin supports to fit in your larger joists and if you are making a room, you will also need to remove the tie bars, remembering that the roof can spread or collapse (very quickly) if it is not supported properly! Often you will need to do a bit at a time, taking out a single support and building underneath, adding a new support before removing any more. Depending on how well the roof is currently supported (i.e. it might be bordering on the dangerous) you might have to put in several temporary supports before you remove anything. The roof is heavier than you might think!!!
The Building Control department in your local council can advise on all these matters and they will take you to court if your roof alterations hurt anybody!
Anyway, lots of people ask about strengthening floors in the loft and when this is requried/what size timber etc. The science is quite straight-forward. The joist performs 1 or two functions (usually) the first is to support the imposed load of the room: dead weight is the joists, floorboards, fixings etc and the imposed load is the stuff we have in our rooms, whether people, baths etc. The second function that joists often perform, especially in the loft, is to act as a tie beam for the roof or walls so that the weight of the roof does not cause the bottom of the pitch to spread out (imagine folding a piece of paper in half and putting it on the desk like a tent, what happens when you press down on the top of it?). In downstairs rooms the joists will also stop walls from collapsing inwards which might happen if you took out all your floors without supporting the walls first.
Your first question therefore is what weight or force do the joists have to take in order that they don't sag excessively causing ceilings to crack. This is largely dependent on whether the loft will be used as a room (in which case it is the same as all other rooms) or just for some light storage (in which case if you keep the storage above about 3 feet of the supporting wall in the centre then you would probably get away with the existing joists - the sagging after all is largest in the centre of the joist span.
An Architect or Structural Engineer will be able to tell you what the recommended joist sizes are and these are related to the quality of wood (commonly called C16 - weaker or C24 - stronger) and also to the span that the wood has to bridge. If the walls are 2 metres apart then the wood will sag less than if they are 4 metres apart. Unfortunately now these tables are not publically available and are held by an organisation called TRADA (of which architects etc are members). You might be able to get a friend to look for you or ask at your library. These tables might say for instance that a piece of 50 x 220 timber in C16 quality can span a distance of 4.64 metres (or more likely you will have measured 4.5 metres and found the cheapest and smallest size of timber that meets this span as 50 x 220mm). Nobody is checking mm but don't take any big risks because the few more pounds of larger wood will be less than repairing your plastered ceilings when they crack or fall.
If you are planning to fit the joists yourself then you need to be comfortable working out the loadings of the roof (unless you are simply adding in the joists without touching the existing structure). In most cases, in a purlin'd roof, you will need to move purlin supports to fit in your larger joists and if you are making a room, you will also need to remove the tie bars, remembering that the roof can spread or collapse (very quickly) if it is not supported properly! Often you will need to do a bit at a time, taking out a single support and building underneath, adding a new support before removing any more. Depending on how well the roof is currently supported (i.e. it might be bordering on the dangerous) you might have to put in several temporary supports before you remove anything. The roof is heavier than you might think!!!
The Building Control department in your local council can advise on all these matters and they will take you to court if your roof alterations hurt anybody!
Monday, 30 June 2008
Guide to Plastering
Well, I am not a plasterer but I know how to plaster so I thought I might help the world and give my experiences with plastering so that you can have a go.
There are various plasters available and it depends on what you are plastering as to which sort you need. Basically there are undercoat plasters and there are finish plasters. All plasters are classified by the background they are designed to be applied to, some are for backgrounds that suck water a lot and others are for backgrounds that do not. So here is my advice:
1) One coat plaster is only really worthwhile for small areas, try and use separate plasters otherwise.
2) If you choose a plaster designed for low suction for a high suction background, it will crack as it dries. If it is a finish then you will have to start again or do loads of filling.
3) If you choose a plaster designed for high suction for a low suction background, it will take a long time to dry and this will affect the quality of the finish as you trowel it but is generally passable.
4) Make sure you get all the equipment you need ready to go before you start mixing anything. You will ideally need a bucket to mix in - a large one unless you are only plastering a small area (1 bag of finish will do about 10 square metres of wall). You will also need a finishing trowel, a spot board (a smooth board used as a table for the plaster), a hawk and something to get the plaster out of the bucket with. You will need something to mix the plaster with and the most popular are metal mixing paddles that fit into electric drills. You can use a battery drill but ideally it should be at least 18v because a lot of torque is required to stir wet plaster.
5) Finish can only be applied directly to walls that are basically flat and have no areas that suck a lot. If this is not the case, mix up an appropriate undercoat plaster so that it is a creamy consistency slightly tigher than a McDonalds milkshake. It should be able to make shapes in the bucket but it should have a wet look to it.
6) Don't take too long stirring it because it will start to harden but make sure there are no dry bits in it to cause lumps. You might have to use a scraper or something until you are comfortable using the paddle effectively.
7) Empty the bucket of plaster onto the spot board so it is quick and easy to get to. Use a bucket trowel or something similar to remove all the loose plaster from the mixing bucket and if you have an assitant, get them to clean the bucket and mixing paddle in cold water. Don't wash plaster down the sink!!
8) Scrape some of the plaster onto the hawk with the finishing trowel and use the finishing trowel to scrape plaster onto the wall. If you are undercoating, you might need about 10mm of plaster but if the wall is not flat, some areas might be more like 30 or 40mm deep but undercoat plasters can handle this.
9) Make sure that the plaster level is basically flat, you might need to buy a plasterers feather or use a dead flat piece of metal to run across the surface and make sure there are no major bumps or troughs. The flatter you get the undercoat plaster, the easier it will be to finish. Do NOT try and get a finish quality surface, you don't want it to be flat and it will waste time, just get the plaster on and make sure it is generally flat. Put any unused plaster into a bin bag or empty plaster bag and clean your spot board and trowel. Clean tools are happy tools!
10) Once the undercoat plaster starts to get firmer, scratch the surface in a diamond pattern every 4 or 5 inches apart to provide a key for the finish to grip onto.
11) Leave it to dry!
12) Finishing is a different beast, the tolerances are much closer, the plaster is applied more thinly and everything that goes wrong affects the look and might ruin the finish. You can always scratch it and do it again but you don't really want to.
13) The finish is mixed basically like the undercoat plaster to a creamy finish, do not make it too tight otherwise you will not be able to trowel it on.
14) It is very important that all lumps are mixed out of the finish, otherwise you will get holes in your finish that need to be fixed or filled later on.
15) Empty the plaster onto the spot board and wash the bucket and paddle.
16) The finish is applied in two stages, the first needs to be quick and will not be perfect - do not try and make it perfect. Stage one is simply covering the wall with a consistent surface of finish plaster only a few millimetres thick. If you have no lumps you should be able to do this fairly easily. If you get any major holes while you are skimming at this stage then put plaster over the top but you must do this now or wait until the plaster starts going off or you will pull the plaster from the wall.
17) You can trowel over any major marks AS YOU GO but do not be tempted to go back over previous plaster to correct things until stage 2. The end of stage 1 is to have a fairly flat but not perfect layer of plaster over the whole wall. When you are first learning to plaster, you will be slow which is why you should start with a small wall and then work up to a larger one.
18) Wait until the plaster starts to go off, that means if you put your finger onto it and pull away, it will not cause a little peak but will leave a finger mark. This means you are ready to start the trowelling and repairing.
19) At this point your wall will have various levels of defects so work in stages starting with the major defects and work down to the smaller ones. Using a wet trowel, flatten out any lines or peaks and if you have holes, take some of your existing plaster (do NOT mix up more plaster) and carefully push this into the holes as you trowel them. The more you do, the better your wall will become and you either stop when you are happy with the finish or when the plaster has dried so much that it will not trowel any more. Make sure you keep your trowel wet or it will pull plaster off of the wall. It is worth investing in a nice trowel for £30ish which will make trowelling much easier to do, especially when you are learning.
20) Any defects after the wall has dried can be sanded or filled with fine fill but unless you have plastered a lot, do not expect perfection here.
There are various plasters available and it depends on what you are plastering as to which sort you need. Basically there are undercoat plasters and there are finish plasters. All plasters are classified by the background they are designed to be applied to, some are for backgrounds that suck water a lot and others are for backgrounds that do not. So here is my advice:
1) One coat plaster is only really worthwhile for small areas, try and use separate plasters otherwise.
2) If you choose a plaster designed for low suction for a high suction background, it will crack as it dries. If it is a finish then you will have to start again or do loads of filling.
3) If you choose a plaster designed for high suction for a low suction background, it will take a long time to dry and this will affect the quality of the finish as you trowel it but is generally passable.
4) Make sure you get all the equipment you need ready to go before you start mixing anything. You will ideally need a bucket to mix in - a large one unless you are only plastering a small area (1 bag of finish will do about 10 square metres of wall). You will also need a finishing trowel, a spot board (a smooth board used as a table for the plaster), a hawk and something to get the plaster out of the bucket with. You will need something to mix the plaster with and the most popular are metal mixing paddles that fit into electric drills. You can use a battery drill but ideally it should be at least 18v because a lot of torque is required to stir wet plaster.
5) Finish can only be applied directly to walls that are basically flat and have no areas that suck a lot. If this is not the case, mix up an appropriate undercoat plaster so that it is a creamy consistency slightly tigher than a McDonalds milkshake. It should be able to make shapes in the bucket but it should have a wet look to it.
6) Don't take too long stirring it because it will start to harden but make sure there are no dry bits in it to cause lumps. You might have to use a scraper or something until you are comfortable using the paddle effectively.
7) Empty the bucket of plaster onto the spot board so it is quick and easy to get to. Use a bucket trowel or something similar to remove all the loose plaster from the mixing bucket and if you have an assitant, get them to clean the bucket and mixing paddle in cold water. Don't wash plaster down the sink!!
8) Scrape some of the plaster onto the hawk with the finishing trowel and use the finishing trowel to scrape plaster onto the wall. If you are undercoating, you might need about 10mm of plaster but if the wall is not flat, some areas might be more like 30 or 40mm deep but undercoat plasters can handle this.
9) Make sure that the plaster level is basically flat, you might need to buy a plasterers feather or use a dead flat piece of metal to run across the surface and make sure there are no major bumps or troughs. The flatter you get the undercoat plaster, the easier it will be to finish. Do NOT try and get a finish quality surface, you don't want it to be flat and it will waste time, just get the plaster on and make sure it is generally flat. Put any unused plaster into a bin bag or empty plaster bag and clean your spot board and trowel. Clean tools are happy tools!
10) Once the undercoat plaster starts to get firmer, scratch the surface in a diamond pattern every 4 or 5 inches apart to provide a key for the finish to grip onto.
11) Leave it to dry!
12) Finishing is a different beast, the tolerances are much closer, the plaster is applied more thinly and everything that goes wrong affects the look and might ruin the finish. You can always scratch it and do it again but you don't really want to.
13) The finish is mixed basically like the undercoat plaster to a creamy finish, do not make it too tight otherwise you will not be able to trowel it on.
14) It is very important that all lumps are mixed out of the finish, otherwise you will get holes in your finish that need to be fixed or filled later on.
15) Empty the plaster onto the spot board and wash the bucket and paddle.
16) The finish is applied in two stages, the first needs to be quick and will not be perfect - do not try and make it perfect. Stage one is simply covering the wall with a consistent surface of finish plaster only a few millimetres thick. If you have no lumps you should be able to do this fairly easily. If you get any major holes while you are skimming at this stage then put plaster over the top but you must do this now or wait until the plaster starts going off or you will pull the plaster from the wall.
17) You can trowel over any major marks AS YOU GO but do not be tempted to go back over previous plaster to correct things until stage 2. The end of stage 1 is to have a fairly flat but not perfect layer of plaster over the whole wall. When you are first learning to plaster, you will be slow which is why you should start with a small wall and then work up to a larger one.
18) Wait until the plaster starts to go off, that means if you put your finger onto it and pull away, it will not cause a little peak but will leave a finger mark. This means you are ready to start the trowelling and repairing.
19) At this point your wall will have various levels of defects so work in stages starting with the major defects and work down to the smaller ones. Using a wet trowel, flatten out any lines or peaks and if you have holes, take some of your existing plaster (do NOT mix up more plaster) and carefully push this into the holes as you trowel them. The more you do, the better your wall will become and you either stop when you are happy with the finish or when the plaster has dried so much that it will not trowel any more. Make sure you keep your trowel wet or it will pull plaster off of the wall. It is worth investing in a nice trowel for £30ish which will make trowelling much easier to do, especially when you are learning.
20) Any defects after the wall has dried can be sanded or filled with fine fill but unless you have plastered a lot, do not expect perfection here.
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