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Wednesday, 17 December 2014

Lime wash on, it can be hot in the winter!

Welsh Lime Works have finished my house!! Hooray. They have managed to work around the scaffolding and all the problems left by the last lime company to produce a lovely white house.

The final coat to this lime putty render has been the limewash. There are a number of special properties to this covering, firstly it is the same lime as was used in the render mix, i.e. a limestone derived lime. This is important when rendering (as opposed to plastering) as it is a hard wearing material. Some limewashes in the past were chalk based as they expected them to be used internally, but you will need a limestone based limewash.

Secondly, the boys (and girl) put the limewash on as a 'hot mix', so basically they used quicklime to make up the limewash just before it was applied and this meant that the limewash went on hot (due to the slaking process). Welsh Lime Works think that this provides a better longer lasting finish due to the reaction that is ongoing when it is applied, so it bonds better with the underlying render. Great to see steaming 'paint' being applied to your house, especially in the winter months (mine you it was still above 5 degrees when it was done).

I have been very impressed with the level of skill and knowledge from Welsh Lime Works and their attention to detail. The house was also left nice and clean.

Scaffolding Abandoned

I have had scaffolding left at my house for the past few months that I have been desperate to get rid of, but will the scaffolder come and collect?? The heck he will. Unbelievable.

The scaffolder was arranged by the original company who walked off site and left me in the lurch, so no happy with either of them.

In the end I have been forced into drastic action, thanks in part to a great piece of advice from Citizens Advice that sets out what you can and cannot do. So I will be selling the scaffolding off and then giving the company any proceeds.

Tuesday, 2 December 2014

Plastering. Is it the same as Rendering?

Plastering with gypsum is obviously different from rendering with sand and cement

When doing 'conventional' works to buildings it is a clear distinction of trades between internal and external works. This is because there is a difference in some of the materials used and also because there is a large enough market to have specialist firms doing one operation or the other.

In the lime world, it tends to be that people do both rendering and plastering. This is driven by the fact that the materials used can be much more similar. Most people will use a NHL Hydraulic lime for both internal and external works.

If you look for a Lime Render course you will generally find one day courses that cover both plastering and rendering as well as everything else lime!

Given that plastering and rendering courses are normally at least two years long it seems a bit much to expect people to be able to render and plaster with lime after a couple of hours. Maybe this is why lime can have an application issue attached to it. After all lime is a much less predicable material than cement and gypsum. 

Having seen the boys from Welsh Lime Works doing a very professional job on my house you realise that that there is no substitute for experience and knowledge. There have been a number of key points in the work where you just know that someone who has just done internal lime plastering would have made some fundamental mistakes.

Welsh Lime Works are keen that their workmanship and knowledge that has been built up over the years is not shared carelessly, so if you want any info I would recommend getting in touch direct with them. However I think that it is fair to say that the key points around door and window reveals, wall corners and floor junctions are where their work stands out and will pass the test of time where others may well fail. Not to mention the issues around potential lamination of the render. All of these key factors require a professionals eye and years of experience in order to get right. So it has been fascinating seeing the process, the method of application, the changes in mixes, the subtlety in timings etc.

So if you have been on a lime plastering course be very aware that applying lime externally is very different from doing the same internally. The effects of the weather, temperatures, orientation and the various pressures on the fabric due to the use of the building all need to be taken into account if the job is to be a long lasting and high quality one.

Extractors and wind

Most extractor fans come with a basic louvres system to reduce back draughts
Most houses have extract fans fitted to them, mostly in our bathrooms and kitchens. However, we rarely think about which way they are facing. Most commonly they are fitted to the nearest wall, simple.

The UK is one of the windiest countries in the world and so the chances are that the prevailing wind will have a large influence on the effectiveness of the extractor, especially if it is facing west. Anyone who has a west facing extractor will be very aware of the level of noise generated by flapping louvres and also by back draughts and the inability of the fan to clear the room of water vapour. So, if possible fit fans away from the prevailing wind so that they can function properly and quietly.

Fitting fans to the lee sides of a building is not always possible, so what to do then?

There are a couple of solutions, firstly you could fix an in-line back draught shutter system. I haven't tried these myself, but they are on the market and should provide you with some protection, however if the fan is on and the wind blowing then my money is on the wind winning! One also fears that they too might suffer from acoustic issues.

Back draught shutters can be used to create a better solution but may still rattle around and also be blown shut when trying to extract
The system that I have used at home is to replace the louvres with a louvres and hood combo. This has altered how the system works quite dramatically for us. The two bathrooms are much quieter and the fan seems to be more effective.

The basics are that the fan can now work without fighting the wind so much and also that the protection stops the rattling of the louvres as the pressure changes due to the wind are now just coming from below. It also has the advantage of protecting the vent from the rain more.
A simple hood to go over the louvres can help reduce noise and also protect against wind driven rain
So it is worth having a think about extractors and how well they are working and what, if anything, can be done to improve their efficacy.