Step by step guide to making dust…..sorry, I mean fixing up your lath and plaster ceiling!
Traditional lath and plaster ceilings and walls, (or lathe and plaster depending on your spelling!), really add to the charm and feel of living in a period house. Unfortunately, lath & plaster is prone to cracking, sagging or even partially falling down. The good news is that it’s often possible to repair lath & plaster ceilings (and walls) and make them last a while longer, (it depends on what look you’re aiming for and of course your budget).
However, since you are here, you might have a sagging ceiling or one that is badly cracked and falling off the laths. Arguably you could be justified in removing the plaster and/or the laths altogether and starting over. Or you might want plasterboard (sheet-rock in the USA) right from the outset, recessed down-lights in the ceiling being the usual culprit!
OK, lets take a look at your plasterwork and go through your options. Its a long page but there’s a lot to explain!
Caveats first though OK. This ‘how to’ explains how to carry out repairs and/or to take down a lath and plaster ceiling that you might want (and have permission) to remove. Plaster ceilings in some listed houses may need to be retained and repaired rather than removed (check first!). If this page tempts you into tackling this job yourself, please jump down and read my safety info first!
Also, I have linked to various external info and suppliers where it’s useful. Places like English Heritage, because they have good info about looking after old houses.
OK, enough blurb, lets get started……
Evaluating whether to remove your lath and plaster ceilings
Stand underneath one corner of your ceiling on a suitable ladder and with your head almost touching the ceiling look across the surface, do a 90 degree sweep looking for any unevenness, sagging sections, cracks etc. Try again from the opposing corners. Your ceiling may look flat from the floor, but once you get up there and have a closer look, you will get a much better idea of its condition.
A sagging ceiling does not necessarily mean that the plasterwork has broken away from the lath though. Old houses settle and the ceilings go along for the ride. So, if your ceiling is sagging or sloping, it may still be OK.
If there are areas where you suspect that the plaster has separated from the lath gently push upwards with the palm of your hands. A little give is normal but if you feel the plaster move up and down, this means that it is not attached to the laths. Dust and debris may fall from cracks as you do this.
NOTE: Don’t go crazy here, if you push and shove a really bad ceiling hard a few times, you might end up ‘wearing’ it! Go gently 😕
Sometimes the lime mortar or plasterwork separates from the laths and drops down. Effectively this means that the plasterwork is hanging underneath the supporting laths and joists, virtually unsupported. Sometimes it is only the horse hair strands in the mortar that is holding up the plasterwork!
If left in this perilous state, chunks of plasterwork will eventually start to crack and even drop away, either in small pieces or in large sheets if there is a water leak or even someone jumping on the floor above etc.
Because repairing a lath and plaster ceiling like this can be expensive, you might make the decision to remove it completely and replace it with plasterboard.
However, we are getting ahead of ourselves, as there may be alternatives to completely removing all the plaster and laths in your ceilings.
Alternatives to removing a bad lath and plaster ceiling….
Over-boarding with plasterboard
- A lath and plaster ceiling can be left in place and ‘over-boarded’ with plasterboard, using long drywall screws through the existing lath and plaster into the joists (not ideal but, quite commonly done). You will hear this option discussed a lot, hence being first in this list! (Or for overboarding “plus”…….)
- Screw 25mm x 50mm battens underneath all of the existing joists. This ‘sandwiches’ and supports the old plasterwork. The battens can also be packed level/flat using thin plastic or timber ‘shims’ as they are screwed tight. Plasterboards are then fitted as normal, (sometimes incorporating insulation and a vapour barrier).
Repairing limited damage or cracks in lath and plaster (ceilings and walls)
- If your ceiling has some cracking but feels pretty secure otherwise, then the cracks can be repaired. Scrape or brush out loose material from the cracks and fill using decorators filler. Fine cracks could be filled with a flexible decorators caulk and smoothed over with a filling knife.
- A sound (ish!) lath and plaster ceilings appearance can be improved greatly by the use of a good quality, thick lining paper. Lining paper has the benefit of ‘tightening’ everything up and giving the ceiling an uniform look. It can then be decorated however you wish (ironically, some are painted to look ‘distressed’!?!).
- Small areas of missing or loose plasterwork can be re-plastered, preferably using similar haired lime based mortars and plasters. If these are not available to you, then areas can be re-plastered using modern lightweight backing plasters and finish plaster. Ensure that loose plaster and dust is removed and damp the area a little before re-plastering. Ask at your local builders merchant for suitable plasters.
Re-plastering with traditional lime based mortar and plasters
- A rare alternative to complete removal, is the removal of the sagging and broken plasterwork and re-plastering the original laths (assuming they are OK) with a suitable haired lime mortar and lime finish plaster. You will need access to the top of the laths to clear away the ‘keys’ or mortar ‘snots’ that were pushed through the gaps in the lath the first time. A specialist job in effect.
Fully repairing a ‘protected’ lath and plaster ceiling
- This goes beyond what I intended to write about here, but of course given enough time and money even the worst ceilings can be rescued, as you would to satisfy the authorities if your ceilings were historically valuable.
- Briefly, the plasterwork is gently supported from underneath and working from the top all broken keys, dust and often centuries of debris are carefully removed.
- Repairs can then be carried out using stabilizing chemicals, wire mesh and adhesives or plasters, with the aim of reattaching the plasterwork below.
- Complicated, expensive, not your average DIY project and arguably beyond even the average builder.
And when all else fails……………
How to completely remove a lath and plaster ceiling….
Tools you will need
Fortunately you don’t need many and you may already have them in your tool kit.
- Working platform, sturdy step ladders or builders trestles etc
- Claw hammer or other lightish hammer.
- Gauging or brick trowel.
- Crow or wrecking bar or the awesome ‘Roughneck‘ ceiling killer!
- Pick axe (optional but useful for getting the old lathes down if you don’t have the Roughneck).
- Clean up gear. Shovel, sweeping brush, dustpan etc and vacuum cleaner (preferably not the missus’s best one!).
Other gear that you may need
- Dust protection such as Polythene and dustsheets.
- Rubble sacks (or Gorilla style tubs if you have a skip).
- Electrical screwdrivers for removing old light fittings.
- Temporary lighting if required.
Additional things to consider…..
It gets messy?……Oh yeah. It gets really, really, really messy. Seriously, it makes so much dust that I recommend that you remove everything from the room and seal off the doors with masking tape before you start. (Oh, and in case you were wondering, this kitchen was coming out. You can also just make out the trestles which, when coupled with scaffold battens made a perfect working platform for removing this high ceiling).
All that mess comes from dust that accumulates on top of your old plasterwork and from within the plasterwork itself. The dust is very fine in particle size and it gets everywhere, really, I mean it, everywhere!
If you have to sheet down some stuff, I would recommend that you include a polythene layer as the dust is often fine enough to go through the average dust sheet. Don’t ask me how I discovered that little gem!
Once the room is cleared and sheeted down, including the floor, you may need to install your temporary lighting and remove any light fittings in the ceiling and make safe any wires that you disconnect (don’t forget to isolate the supply first!). Obviously if you tackle the job in broad daylight and there are windows……
Bit obvious this one, but you should open any windows if you can and don’t forget your dust mask!
Step by step guide to remove your lath and plaster ceiling….
Removing a lath and plaster ceiling is a three stage process (assuming that you are removing it from underneath). Read removing lath and plaster from above if applicable.
- Remove the plaster using a claw hammer or similar and a stout trowel. Working in front of yourself, tap the plasterwork with your hammer to break it up and if it doesn’t drop away, keep tapping it and then either use the claw on your hammer or lever the plasterwork off with the trowel. On really poor ceilings the trowel can be slid underneath the plasterwork and large pieces can be levered away. NB: It’s really important to clear away at the end of this stage when all the plaster is on the floor. You don’t need to sweep up necessarily, just get the big stuff cleared away using a shovel (otherwise the next stage will make a huge pile of lath reinforced plaster that is a bugger to clear up!).
- The next step is to remove the laths. I usually use a ‘pick axe’ of all things! I slide the blade through a few laths and then place the head of the pick-axe onto the bottom of a joist and lever down large sections of laths. You might want to start small and use a claw hammer or pry bar (crow bar). The laths usually break into smallish sections. I can recommend the ‘Roughneck‘ bar though, it makes the job easy.
- The final step is to remove the nails (apart from clearing up!) that were holding up the laths. This is usually fairly tedious and time consuming as they are very numerous and rusty. Oh, and you must not miss any, not even one. Believe me, you will curse when you are plaster-boarding if you try to put a board up and there is a nail in the middle somewhere! Sometimes you can pull them out with a claw hammer or pry bar, sometimes they snap off sideways with a blow from the hammer and sometimes you just need to hammer them in! You’ll work out what’s best for your job quickly enough.
Time for a cup of coffee and a break to let the dust settle 😀 .
Back so soon? Right, next is the boring clearing up bit.
- Start with gathering up all the fallen laths, breaking up any long lengths and put into rubble sacks, skip or wood pile for burning.
- Now you will see lots of plaster on the floor again. This is the mortar (snots, nibs or keys) that was sitting on top of the laths after being pushed up through the gaps in the laths to provide a key for the plasterwork. Scrape up the mortar with a shovel or dustpan and remove again.
- That leaves the dust. This can be swept up and bagged for disposal. You might want to try minimizing the airborne dust by damping down with a garden sprayer, but I’ll be honest, it is not that effective and the existing mess will be considerable anyway.
Now you are ready for re-boarding with plasterboard, but first you will probably be getting the electrician to install new cables for those fancy new down-lights that you want!
- TIP 1: Don’t forget to grab a pencil and put a vertical mark on the wall about an inch and a half long (40mm) that indicates where the center of the joist is. This makes finding your fixing point so much easier when you are boarding.
- TIP 2: If the ceiling joists are anything other than straight across along the whole length, i.e. if there is any ‘trimmed’ areas that won’t be logical once the plasterboard has been offered up. Consider taking photographs of the joist layout; you’ll be glad you did if you get stuck and can’t find anything to fix to once you are boarding!
- Tip 3: Now is a good time to check the joists for ‘flatness’, extra timber can be fixed to the joists to level up slopes or dips etc at this stage. Some people even ‘cross batten’ the ceiling with 2″x2″ timber at 90 degrees to the joists..
Hopefully that gives you a good understanding of what’s involved in taking down a lath and plaster ceiling or even how to repair your plaster and lath ceiling. Make no mistake, tackling lath & plaster is not a decision to take lightly and certainly not a job to attempt yourself, unless you can tolerate a heck of a lot of mess and drama for a few hours.
Related useful information
Removing a lath and plaster ceiling from above
I’ll briefly mention removing a ceiling from above, as it is a popular method if you have access to a ceiling from above, especially on a full renovation job of an empty house.
Working from above you can push the whole lath and plaster ceiling down into the room below, using a shovel, sledge hammer or even their boots. Simply tap the back of the laths close to and either side of the joists with your preferred tool (I recommend a lightish long handled 7lb sledgehammer)
I don’t use this method as I find that the lathes and mortar become all mixed up, making the heap of debris very difficult to clear up. Arguably though, I can see the merits of working from above, however, great care must be taken not to fall through the joists. For this reason alone I would NOT recommend removing lath and plaster ceilings from above, unless you are a pro, but then you wouldn’t be reading this would you
My Top Ten Ways to Repair Lath and Plaster
This is a short summary of some of the ways you can repair the lath and plaster in your home, depending upon the look you want to achieve, the time you want to spend on it and of course, your budget.
- Re-decorate as it is. Vacuum to remove dust, (wash down, if required) and then re-decorate with suitable water based paint. Not a good repair if the plasterwork has gone beyond the cracking stage, i.e. sagging badly. Depends on original plasterwork condition.
- Cost: Very economical and quick.
- Pros: Period charm in abundance. Ideal for very old cottages that don’t have a straight edge or surface in them. Shows imperfections.
- Cons: Potentially dangerous and possibly very short term solution for damaged plasterwork. Not a ‘flat’ finish. Shows imperfections!
- Fill the cracks and blemishes. Scrape out all cracks and vacuum out loose material. Fill cracks and small blemishes with decorators’ filler using a suitably sized scraper or drywall spreader. Gently sand the filler flat and vacuum all dust away. Wash down if required and re-decorate.
- Cost: Economical repair.
- Pros: Retains period feel. Looks good initially. Easy and quick repair.
- Cons: Might only last a few years depending on plasterworks original condition.
- Use thick lining paper. Scrape out and fill cracks as No.2. Glue a thick grade of decorating lining paper to the plasterwork. Re-decorate.
- Cost: Reasonably economical repair.
- Pros: Retains period feel. Could gain many more years out of reasonable plasterwork.
- Cons: Relatively difficult on uneven surfaces. Won’t stop further cracking over time if surface is still moving.
- Glue sagging plasterwork back into place. Plasterwork can be ‘glued’ back into place by drilling holes in the plasterwork, vacuuming out the dust and injecting a suitable adhesive. The plasterwork is then gently pushed back into place and supported until the adhesive dries.
- Cost: Medium to high cost, depending on time taken and plasterwork condition.
- Pros: Medium term effectiveness. Retains period feel.
- Cons: Arguably a specialised job and may be too difficult for an effective DIY repair.
- Expose the beams. Completely remove the lath and plaster, de-nail and clear away. Wire brush all plaster marks off the joists. Re-route any wiring, if required and repair any damage, holes in the timberwork etc. Clean up and vacuum all surfaces. Leave as is or decorate with varnish, wood stain, or paint. Usually just used on ceilings (walls sometimes in the USA due to better sawn lath)
- Cost: Economical to medium depending on timberwork condition.
- Pros: All the old plasterwork is removed and finished with newly decorated surfaces.
- Cons: Different look and feel, arguably only suited to certain properties and owners. Difficult electrical wiring and limited choice of light fittings.
- Over board with plasterboard or sheetrock. Find the frame or ceiling joists, mark their position on the wall and then over-board with plasterboard / sheetrock using long (60mm to 75mm) drywall screws into the original timberwork. Board joints are then taped and filled if tapered edge drywall is used or skimmed with finish plaster if square edges boards are used. One of the most common methods to ‘repair’ a lath and plasterwork. If 25mm x 50mm battens are used first underneath the joists, this becomes a good repair as it secures the old plasterwork and allows new wiring and insulation.
- Cost: Medium to high.
- Pros: Effectively a brand new surface is created out of plasterboard/sheetrock.
- Cons: Potential problems with adding additional weight or levels if there is a cornice. Loses that period feel.
- Remove the plasterwork and lath entirely.Replace with plasterboards / sheetrock. Mark positions of all joists and timbers then fix 12.5mm plasterboards to the underside of the original joists using 38mm drywall screws. Board joints are then taped and filled if tapered edge boards are used, or skimmed with finish plaster if square edged boards are used.
- Cost: High. Removal of old material, new boards and finishing makes this one of the most expensive options.
- Pros: Plasterboards/sheetrock are stable and very flat. A permanent repair.
- Cons: Loses the period feel.
- Re plastering keeping the original laths. Removing the existing plasterwork entirely and if the lathwork is sound, re-apply the three coat plasterwork, two base coats and a thin finish coat.
- Cost: High, due to special skills and materials needed.
- Pros: Good as new finish, that also matches the surrounding period work. Long term repair.
- Cons: Arguably not a DIY proposition due to work involving lime plasterwork.
- Heritage quality.Fully support the plasterwork from underneath on blanket covered timber on props or staging. Working from above, gently remove all loose debris, old keys or nibs and dust. Employ one of the various systems available, for example fixing a wire mesh to the inside edges of the joists just above the plasterwork and then applying adhesive to the plasterwork embedding it into the mesh.
- Cost: Expensive due to extreme care needed and labour involved.
- Pros: Retains all original period features. Usually only used on plasterwork of significant historical interest.
- Cons: Arguably not a DIY proposition due to care needed to preserve original features without damage.
- Buy a newer house.Sorry, I couldn’t make ten and nine ways to repair your lath and plaster just didn’t sound right. Any ideas for number ten are most welcome…….
- Cost: Horribly expensive, removal companies, estate agents, lawyers etc.
- Pros: No lath and plaster to repair.
- Cons: Everything is very, very flat, smooth and arguably…..boring.
Need More Information or Help?
Urban legend has it that you only need to read six books on a subject to be classed as an ‘expert’ (not sure what that makes me as I read well over 100 a year!). So, here are some books I found useful in my work on old houses, to get you started!
All available from amazon.co.uk (or here at amazon.com for the rest of the world), just follow the links to have a peek! (it’s a nice way to say thanks for the guide if you buy, as amazon chip in towards my coffee bill!)
Old House Handbook: A Practical Guide to Care and Repair, by Roger Hunt and Marianne Suhr. Hardback.
Don’t be deceived, this book may be at home on the coffee table, but it packs a lot of really useful information into its 208 pages. Passed and approved by my favorite ‘Institute’, the guys at SPAB, the Society for the Protection of Ancient Buildings.
The book teaches you to work with your house, not fight it. Repair not restore or renovate. If you are into minimalistic, white flat surfaces and recessed downlights, this book may be a shock for you, as it educates us to live with a buildings character, not destroy it.
Maintenance of Historic Buildings, A practical Handbookby Jurgen Klemisch.A practical, hands-on guide to the maintenance of your older house. Based on many years of experience, this book teaches you the current best practices related to maintenance and is presented using a straightforward logical format.
In two sections the book deals with maintenance for use by owners and how to conduct condition surveys The book makes extensive use of helpful checklists, work cards detailing routine cleaning, deep cleaning, inspection, servicing and redecoration; and even spreadsheets to help plan your maintenance. Following the books recommendations would over time build a useful record about your house, which will be helpful when deciding the timing of future repairs and allow you to assess costs accurately.
The Damp House: A Guide to the Causes and Treatment of Dampness. By Jonathan Hetreed. Hardback.
I thought that I would include this book because as the owner of an older property you will soon come to learn that water or damp is the mortal enemy of your house!
Managing the moisture and water, on, in and around your home is vital in the battle to preserve and protect it.
From the patio to the ridge, water is trying to get into your house and cause damage! Read Jonathan’s insights and learn how to keep it at bay.
Using Natural Finishes: Lime and Clay Based Plasters, Renders and Paints – A Step-by-step Guide By Adam Weismann
Adam Weismann’s book is more specialized than those above and would suit the hard core enthusiast who wants to have a go at repairing their old walls and ceilings themselves.
Kevin McCloud from Grand Designs comments that it is “A splendid book. A real addition to what’s out there and very complementary to the Society for the Protection of Ancient Buildings’ new technical manual on Old Building Repairs”.
Lastly and most importantly….
Your Health and Safety.
Lets keep this sensible and I’ll assume that you have plenty of common sense and a reasonable ability regarding DIY.
- Any electrical light fittings should be removed by a competent person, always isolate supplies and make any exposed wires safe. If in doubt get a pro in.
- When removing a lath and plaster ceiling, there is going to be a lot of debris flying around as laths are springy things and can flick bits of plasterwork into your face with some force.
- You will also get covered in dust.
- Rusty of nails can be sharp, as can broken bits of plaster lath.
- Old plaster dust can irritate the skin, especially if sweating.
So, the bare minimum that I wear when taking down and clearing up a lath and plaster ceiling or wall for that matter is:-
- Eye protection, Goggles or safety specs (essential)
- Respiratory protection, Dust masks or preferably a proper face mask (essential)
- Sturdy platform to work from, minimum would be strong stepladder, better would be builders trestles and scaffold battens. (essential)
- Stout footwear, preferably with steel toecaps (pretty essential)
- Gloves (pretty essential, depending on how ‘tough’ you are!)
- Disposable ‘cover alls‘ (one piece suit) to cover everything, the spaceman type! (optional but nice)
If you don’t have any safety gear then, Screwfix or Tooled Up can supply you and don’t be tempted to skimp on safety gear, nothing costs more than a few pounds! You wouldn’t risk your eyes for a fiver would you? (read my post [intlink id="1459" type="post"]about eye injuries[/intlink] if you need convincing).
Lath and plaster carpet
Bev Hisey was so inspired by the look and feel of the lath and plaster when renovating her home that she has dedicated a brand new carpet design to it! Click the image to see more…
As usual this page is a work in progress so feel free to leave comments to tell me how to do it properly