With a traditional lime finish coat, the plasterer becomes a chemist. “This is where art meets science,” Bob says, as he watches the mix being prepared for the lime putty. If cold air is trapped in the void then your chimney breast will most likely be at a different temperature to the rest of the room, which in most situations will cause a cold spot or a cold wall where moisture in the air will then condense and cause a damp patch. If you have now identified the cause of your efflorescence of salting issues it’s time to see how they can now be fixed.

To do this job there are special metal “combs”, but these are only really necessary when you are trying to cover over about 40 square m in one go. The average novice should aim for a maximum of 4 square metres in one go. This is because framed areas tend to get colder, allowing warmer moisture to collect and cause discoloration. Most Common Causes Sephy (a Cross) and Callum (a Nought) have known each other their whole lives. In their teens, they begin a secret romance, but relationships between noughts and Crosses are discouraged. Noughts and Crosses usually live separately and attend separate schools, but when Callum becomes one of the first noughts to attend a mixed school (the school Sephy goes to) their relationship is seriously tested. On areas which require a large amount of 'building up' it makes sense to apply some type of filler (for example expanding foam) so that you do not have to apply lots and lots of thin coats of bonding or browning plaster.

Causes of Cold and Damp Spots on Internal and External Walls

There is another type of salt deposit known as ‘salts’ that appears as a crunchy, raised white deposit. If there is moisture present it may be worth considering adding a vented cap or cowl to your chimney pots and seeing if this resolves the issue. Easy to apply and spread. Use for walls and ceilings with a smooth finish, or as a base coat on surfaces. Whichever solution you use, ensure that the walls surface is correctly prepared first and tha new plaster is laid on and allowed enough time to fully dry. As mentioned in the title, the tell-tale signs of this issue tends to be cold spots and damp spots on your interior walls just above the skirting boards.

The tell-tale signs of this are damp around the base of the chimney breast, as the moisture rises up from the inside. Carlite plaster: Also used as a finishing coat and suitable for a wide range of substructures, this type of plaster takes longer to set than Thistle. Often, these issues are more apparent around chimney breasts (chimney salts) where the action of burning fossil fuels releases minerals, among many of them hygroscopic salts, that can condense on the inside of a chimney breast. Each pass on the hardening plaster should see more and more trowel marks and bumps disappearing. When the plaster is almost fully hard, your final pass will trowel it to a lovely flat finish. Examples of topcoats include dri-coat, thistle, and carlite plaster. More so, one coat plaster can be added to this list as it can serve as both and is an excellent option for small repair jobs. How Much Does a Plasterer Cost?You can apply a damp and stain primer to prevent any staining caused by the damp showing through on the newly decorated surfaces. Once the treated wall is dry you can then redecorate as required. This then allows cold air and moisture to penetrate the external wall and access the inner cavity wall, making existing cold and damp spots worse and also creating new ones.

A characteristic of hygroscopic damp is that damp patches will come and go over time, so if yours do this then theres a good chance your damp spot issues are salt-related. A: While the results are usually glorious, plastering is one of the messiest jobs out there, and you should know this before embarking on it. If you want to DIY, then ensure that you clear the room of all furniture and other fixtures as there will be a lot of dust hanging around. Also, it is advised that you mix the plaster in an open-air area, so you don’t inhale too much dust. The reaction is complete when the slaked lime stops giving off heat. At this point it is ready to be mixed into putty.If you have cold and damp spots isolated to the area around your chimney breast then these will need to be delt with before any repairs can be pt in to action. Issue Caused on and Around Chimney Breasts Once you have located it, inspect the area around it for damage to mortar, plaster etc. and also test for damp and whether the area is colder than the surrounding surface.

Thistle plaster: This brand name from British Gypsum but has become shorthand for a finish coat and can be used on plasterboard, or as part of a two-coat system. Take your feather edge or what ever straight edge you’re using (preferably metal rather than timber) and lay it across the two beads on either side at the bottom of the section you have filled. You may be familiar with rosin in its natural form as used by players of stringed instruments but if you've developed an allergy to Elastoplast you should watch out for the colophony in a wide range of other everyday items. In the European Union all products containing more than 1% colophony have to be labelled with an allergy warning.Bathroom leaks are one of the most likely causes of brown ceiling stains. In these cases, the brown spots will usually appear below a bathroom or ensuite. Other visual signs can be a damp chimney breast and ceiling, damp walls either side of your chimney breast, damp in your loft or attic space around the chimney area or even damp halfway up a chimney breast. For full information on skim coat plaster including how to mix it, lay it on and finish it, see our skim coat plastering project here.