Garden Room Workshop: Part 16. Plasterboarding

welcome back in the last video we covered how I insulated the walls of my garden room along with the vapor barrier and in this video I plasterboard and put up the cement board in the shower room plus there's a bonus resource at the end the first half is theory and the second is action there's a lot to say so let's get cracking let's first look at a couple of other options for internal finishes because plasterboard won't sue everyone for workshops it's very handy to be able to throw in a screw or nail to hang your tools pretty much anywhere on the walls you like without first having to locate your studs so oh s be your pliers perfect for this and both can be painted to help hide the fixing screws and to brighten the room however as you'll have discovered by this point neither a cheap but at least you can opt for the thinnest stuff and it doesn't need to be exterior grade with ply you can take it up a notch by creating shadow gaps with a bit of black spray-paint grab adhesive and a few nails pine cladding can look great if you're after a summer house beach hut type look either painted or with a bit of oil or you can get adventurous with reclaimed timber or pallet wood I wasn't very brave though so I stuck with plasterboard it's surprisingly low cost and you can always change the appearance with different kind of paints or wallpaper or maybe even some peel and stick vinyl for a good feature wall there are two different ways of finishing plaster board you can either go for a full skim which is common here in the UK or you can tape and joint which is essentially plastering between the sheets and leaving the main face of the plaster board bare it's conventional wisdom that full skin plastering is a skill that takes a lot of practice and there's nothing worse than a bad plastering job I watch a lot of US channels and they make tape and jointing look pretty easy and fun and having recently shelled out for grounds work electrics and plumbing I thought that I'd give it a go rather than hire a plasterer and after all this is a DIY channel I'll give you my thoughts on which might be the better choice in the next video but your decision between the two methods will inform your choice of plaster board as square-edged plaster board is typically used for full skin whereas tapered edge plaster board is designed for tape and jointing however if you're at the plaster boarding stage and haven't yet decided how to plaster go for a tapered edge because that can be used with either method so which way should past board be orientated hang it horizontally helps deal with wonky stud work but hopefully you've done a marvelous job so that shouldn't be such a consideration however horizontal hanging provides a greater structural benefit by tying together more of the studs to one sheet there as I have OSB on the outside of the walls doing that job it wasn't a concern but and I'm going off on a tangent here if you want to keep the total project cost down you can forego having OSB sheathing and just staple the breathable membrane directly to the outer side of the studs so in that case hanging plaster board horizontally will be very beneficial to increase wall rigidity adding more noggins in the wall can help to of course tapered edge plasterboard only has a taper on the two long sides of the plaster board not on the shorter sides so my plan from the outset was to attach the plaster board vertically on the walls so the only short non tapered sides that I would have to tape and joint would be on the ceiling plaster board and these are called butt joints a solid plan except for one big problem my studs and indeed my roof joists are on 16 inch centers which is perfect for OSB imply in 8 by 4 feet sheets but as it turns out PLAs board only comes in 1200 millimeter width which suits 400 millimeter centers but not my 16 inches as it comes up short on the last stud now I'm not completed yet I did look up where the plaster board came in 8 by 4 sheets before starting the build and I found that it did but when it came to ordering every company I called said oh yeah that's a typo hmm our strange half metric half imperial system ruining my best laid plans so how am I gonna solve this I could cut back the plaster board to the previous stud but that creates a lot of wasted plaster board and defeats the purpose of hanging it vertically and I've end up with one square edge each joint if I turn a 1200 by 2400 millimeter board horizontally that's better I still have to cut it back but there's less waste and I keep most of the tapered edge even if I do end up with a few butt joints however while the width of plaster board is fixed at 1200 millimeters the length you can get it in varies I asked gyproc a plaster board manufacturer why these exact lengths exist and apparently they're for different height ceilings when vertically however I also figure something else out if we bring back the span tables at the top it shows the conventional spacings 400 450 and 600 millimeters and all of these lengths plaster boards are divisible by one or more of the different spacings so that when hung horizontally the ends of the passport line or the center of the studs mm-hmm that's good to know all with the exception that is of 2500 millimeter but I'm glad it exists because that's how I'm gonna solve my problem I only need to cut six centimeters off it to reduce it to eight feet long and it was only a little more expensive than the standard 1200 but 2,400 sheets so I feel a bit of a plum code not knowing all this but you don't know what you don't know and the learning is in the doing plus I promised in part one that I'd show all my mistakes so you'd have to make the same ones so what's the wider lesson here is metric or Imperial spacing best for studs and joists if plaster wall doesn't come in imperial maybe we could find OSB in metric a scoured about 50 builders merchants online big and small and there's no doubt that the Imperial size boards are far more common however wicks Travis Perkins and SELCO as examples all stock a twelve hundred by twenty four hundred nine millimeter board which would do nicely for the outer walls for floor and ceiling joists we need eighteen millimeter and the scant evidence that this exists in that same sheet size it does come in a five ninety by twenty four hundred millimeter size that is also tongue and groove so that fits four hundred millimeter or six hundred millimeter centers it's smaller and therefore lighter to get on the roof and the tongue and groove allows for some expansion while also locking together more tightly so the rubber roof looks smoother when laid down on top so if I were to do it all over again I would on balance I think go for four hundred millimeter centers but it's hardly a clear-cut decision I'll pin a comment to previous videos as I don't want to mislead anyone but if you've gone for sixteen inch centers like me don't worry as you'll see plus board is really easy to cut and if you have a view wavy joist it's pretty beneficial to be able to cut it back to the exact size you need rather than coming up short whew that was hard to explain but hopefully it's clarified the issue a little more and you can make a more informed choice based on what size OSB implies available near you thickness of plaster board it comes in three different thicknesses 9.5 12.5 and 15 millimeters twelve point five millimeter is most typically used for four hundred millimeter or 16 inch spacings and the extra rigidity is needed for the ceiling to prevent it from sagging you could use nine point five millimeter for the walls but the price difference is small 15 millimeter tends to be used if you have wider spacings or if you're trying to increase the fire rating or decrease sound transmittance I went with twelve point five millimeter all-round types of plaster board in part 15 we discovered there are oil backed and insulated versions but there are variations of the actual platform material - acoustic plaster board is designed to deaden sound it's usually blue in color and a good choice if you're concerned about noise from a workshop or music studio moisture resistant plaster board comes in and is regularly used for bathrooms to prevent mold from growing fire-resistant plasterboard comes in an appropriate red color and is use for we're building regs requires increase fire ratings such as around RS J's as far as I'm aware this isn't required for garden room walls on boundaries I'm still researching this topic but it seems the focus of non combustible tea is on the outer cladding and then of course there is the standard ivory colored plaster board all plaster board has a good degree of fire and moisture resistance and dedan sound as well so the standard types due to my needs and probably will do for you too so in summary my plaster board is tapered edge 1200 by 2500 millimeter twelve point five millimeter thick and is the standard ivory face stuff Marney manufactured by british gypsum though now from GTECH are similarly priced and I'm sure more or less identical I bought through a company called CCF who delivered to the driveway the heavy so to lug them into the gun room I decided to buy a plaster board carrier rather than the string method that I've used previously for other sheet material as I thought the string might damage the last board as a general point I have always tried to make do with what I have around me as you'll see in a minute but as I've progressed through this build I've slowly come to the conclusion that having the right tool for the job is optimal if you could afford it of course anyway my friend Steve came over and we set about cutting the plaster board to length which is pretty simple you score the front face of the plaster board once or twice with a utility knife and then use a straightedge to snap the past board before bending it backwards and then using the utility knife again to cut through the paper on the other side resulting edge is pretty rough so you have to use a surf form which has a blade a bit like a cheese grater and it just takes a few passes to smooth the edge so where to start it seems like best practice is to start with the ceiling plaster board the main reason being that the wall plaster board supports the edges of the ceiling plaster board it's particularly important along the sidewalls if you haven't got anything to screw up into I position a roof joist there for this very purpose but you can also put a timber or nuggins in at this stage if you like which i think is better than just supporting the edge with the plaster board the other argument is that if there were a fire flames would be stopped from reaching the roof joist by the ceiling plaster board rather than having a direct line upwards way to do the wall plaster board first I should point out that my electrician had all the measurements for the locations of their cables for the dam lighters written down so make sure you have these if you remember I situated my roof joists directly above the studs which at the time meant I didn't have to mark the spacings out and it's a direct transfer of the weight of the roof through the wall studs someone pointed out in the comments that positioning them so wasn't necessary as my double top plate would easily distribute the weight and that's true as you progress through the build having everything lined up is incredibly helpful we started with the back row of plaster board and once lifted to the ceiling you can't see the position of the joist above the back wall but all I had to do was look down to where my studs were and just screw directly above as that's where my joists are the same is true when it comes to the battens on the outside which you want to be attached to the studs but there is being house wrapped block the view of them as my joists are directly above the studs I could just make a mark on the breathable membrane directly below the joist which tell me exactly where my studs are anyway if you want to get the plaster board up quickly you might want to just pop a few screws in to hold it but make sure you at least put them in every joist on the other side of the sheet so when you do the next row and cover up the joist you could just see where the joists are by looking at the screws in the previous row so how to get heavy plasterboard on the ceiling well your best bet is to hire a panel or sheet lifter you turn the wheel and it raises it to the ceiling and hey presto but as I had free labor to make use of I chipped out and instead our Steve to bring his work platform over and I made a t-bar with some spare timber it had longer than the ceiling is high [Music] there are specific plasterboard screws of an american ice to drywall screws opinion differs on the length of screws required but a good rule of thumb is three times the plaster wall thickness so I use 38 millimeter screws spacing of screws is easiest to remember in inches so for sealing Passport they should be spaced 6 inches on the edge and 8 in the field and for wools Fuhrer required spaced at eight inches on the edges and 12 in the field so to get a rough idea of quantities required for two point four meter squared sealing she fifty three screws needed or around twenty two per meter squared and for a wall sheet we need thirty nine or around seventeen per meter squared for vertically hung wall plaster would you need a few more a forty four per sheet so you can work out how many you need and I'd say I had a good twenty percent on as much for your plaster board will be cut down and therefore have more edges they're pretty useful screws so they won't go to waste screws should be tightened so that they depress the paper on the passport but not break through it the depression is particularly important for tape and jointing as you'll be filling these holes so that the plaster ends up flush with the board in order to do this with accuracy you can either use a drywall screwdriver bit the ring of which prevents screwing in too far or you can use a collated screw gun which has to be said is a lot of fun there are also cheaper versions which attach to your drill the screws come on a thread which automatically feeds the gun one after the other I went for the cheaper option though and it goes by pretty fast my tip of the day to those of you juggling a build with work is to leave the jobs like screwing and nailing which neither require getting dirty normally tools to do in between the bigger jobs it's very easy to pick up a drill driver and some screws and fit in an hour here and there over the week and then get out all your saws and tools and do the messy stuff on the weekends so that's why when attaching the plasterboard i only put in enough screws to hold it in place and then came back when i was short on time to do the rest and i use the same tactic when it came to doing my decking next we did the back wall because with no windows it seemed like the easiest we did the top row first in order to get it tightly up to the ceiling [Music] when it came to the bottom row we had to cut out the holes for the plug sockets in the electric stage I'd let my electrician know what thickness of passport I was using so my sockets and plug boxes protrude by 12.5 millimeters and are therefore flush once plasterboard it if you're going for a full skim you may want yours to protrude a little further but it doesn't have to be too precise first we had to mark on the plasterboard where the holes for the sockets were to be which can either be done with some careful measuring or you can place the board on the wall and then use a scrap piece to give it a good whack not too vigorous mine and that creates the outline of the socket on the back of the plas Ford this works really well with the metal back boxes that I have but probably wouldn't with some plastic types once we had them marked out we tried a few different methods but settled on drilling the four corners through to the other side and then scored along the four edges the drilled holes stop your knife from slipping too far then we scored an X in the middle flip the sheet over and then did the same on the other side using the drilled holes to denote the four corners we could then punch through and then clean up using the Sur form again you can also use a serrated knife which I'll show for a different cut later on next we started on the left wall and because my ceiling is sloped we figured it was quicker and easier to start with the bottom row with a level board and then cut the slope and height in one cut to the top row of last board I'm not sure if this is obvious or not but to do so you measure and cut the width then measure the heights on either side transfer these to your board and then that gives you the slope that you need to cut now the bond with the plaster board shouldn't sit on the floor for a few reasons number one plus board is basically compressed dust sandwiched between paper so any spillages on the floor will quickly be soaked up and having the gap prevents this number two it allows for expansion and contraction of the floor and walls and three if you're going fir flooring like laminar it needs to be able to expand and therefore requires a 10 millimeter space all around the edges if you were to plaster board all the way down to the floor a 50 millimeter wide skirting board will only cover five millimeter of the lamina so if it contracts you'll see a gap this is also an issue in houses because where there is carpet originally the skirting goes all the way down to the floor and then you have to use these floor trims to cover the gap if you update to oak or laminate flooring so by raising the plaster board up the flooring can go within 10 millimetres the stud and then the skirting goes on top giving a good 15 millimeter plus room for contraction thicker skirting can help too of course my flooring is 12 millimeters thick and underlay is 5 so we use two off cuts of passport to raise the bottom row up to give enough space to accommodate both and then some extra [Music] next we did the front wall we were in our strive by this point and due to the window and door we did end up doing some vertical sheets here for the right wall I was on my own again you may have noticed the vapour barrier is a different color from the last video I replaced it for a reason I can't call now but in my haste I'd forgotten to cut out the socket here so on the second fix my electrician had to locate it and dig it out no harm done but it's worth double-checking you've cut out all of yours maybe counting them before and after you've done your vapor barrier to make the hole for the radiator conduit I drilled a circle of holes and then use the plasterboard saw to cut it out four sheets next to a door you can use the surf form from the side once attach to the wall for the window above I decided to create a cutout in the center of a sheet and used a regular hand saw which actually works really well and you get a clean cut I suspect that above the top corners of the doors are weak points as I've had a couple of hairline cracks in my plaster I've had to go over again so I reckon that it's better if possible to cut the plasterboard in an L shape so that the two edges meet above the center of the door it creates a bit of waste but might be worth considering for around the windows my original plan was to use whatever timber cladding I used for the outside as window trim to kind of bring the outside in but once I saw how striking Nick's anthracite gray windows looked against the painted reveals I decided to go with that look instead which meant plaster boarding around the windows the big advantage of timber frame versus brick and block cavity is the thinness of the wall so in the small gardens we have in the UK timber framing allows you to maximise the internal floor space but the drawback is you end up with much thinner window reveals as long as you don't intend to put ornaments on your window sill it's fine looks wise it does present a couple of minor issues the first is later on when I fitted recessed blinds they sort of project out a bit more than I'd have ideally liked and the second is fitting the plaster board as you can only get one line of screws in before scoring and folding back which on my first attempt broke the plasterboard at an unwanted angle I first tried using smaller pieces to use up what I had left over the plaster board but that doesn't give much leverage to break the plasterboard and I had to saw off the excess which isn't ideal much better is to use a larger piece as that does give you the leverage but it's tricky to get your arm in behind to cut through on the other side of the paper so I just cut through from the initial side that I'd scored front not the easiest but it works alternatively you could cut a strip of plastic for the right width and just grow it down I had some leftover sheets so decided against using moisture-resistant plasterboard in the shower room and instead use what I had it's not going to get heavy use it has good air extraction so I'm confident it will be fine onto cement boarding I snapped a pic of this handy table in SELCO which shows that while you can toss ceramic onto plaster board in dry areas you can't in wet areas such as in a shower so for wet areas or for heavier tile you need cement board which doesn't weaken or crumble when wet and it's waterproof being composed of cement it's pretty heavy so along with the tile I did wonder about subjecting my floor and foundations to that weight the alternative is to use plastic shower wall panels which actually look pretty good and a very like wait but they're also pricey so I figured that it would be okay and went with some Hardiebacker cement board it's more or less the same thickness as the plaster board I use so the two meet together nicely and comes in at 1200 by 800 millimeter sheet which was very handy as my shower tray is 1200 millimeters long and the height of the wall exactly three boards high so no cutting required here for the other areas I did need to cut it to size the proper way is to use a carbide blade I didn't have that so instead I scored it with a normal utility knife a few dozen times then I gave it a hammer and then I dance a little jig there's always a way to attach I use the same drywall screws as before which worked really well but there's some debate over whether a proper wood screw would be more appropriate if I were using heavier porcelain tiles I'd probably think more deeply about it but so far I've had no issues it's not a problem if the screw heads sit on the surface as they'll be covered by a decent layer of tar adhesive so you can see where the tyre will go by where the cement board is and the rest of the shower room will just be painted plaster board lastly the joints are covered by an alkali resistant mesh tape has one sticky side which you apply to the cement board to which you then apply waterproof tile adhesive which waterproofs the whole thing with no need to tank but that's for another video I want to say a big thanks to Steve plaster boarding really is a two-person job and I would have really struggled without him I returned the favor as steve has been doing some renovations to his house including some interesting soundproofing methods during plaster boarding so I may make a video on that topic at some point I really did thing I get to the tape and jointing in this video but as ever I think of all the things I'd want to know when taking on this project and the video turns out longer than expected so that's going to be the next video in the meantime I have a resource for you I've made a simplified version of the span tables for floor and flat roof joists which can be downloaded from the resources page at the website I've added in some explanations and suggestions pertinent to garden rooms so hopefully that would be a help to many of you and I'll see you on the next one you

Channel: Ali Dymock

Views: 164,544

Keywords: garden room, summerhouse, tiny house, plasterboard, plasterboarding, cement board, drywall, drywalling, how to build a garden room, garden room build, shed, garden office

Id: MsNwe5jHreo

Length: 21min 1sec (1261 seconds)

Published: Tue May 05 2020