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Chimneys Part 2.

The next stage of the chimneys involved relining the drawing room fireplace with a flue, replacing of Pots and application of scud coat.

To line the chamber with a flue an insitu base had to be created to hold the first flue in place. I used concrete reinforced with metal dowels drilled into the stone. To gain access to do this you have to take out some stonework above the fireplace. When your first flue is in place and the concrete has hardened more stonework at intervals of around 1.5 meters has to taken out so as to get to flues in.Image I used a mix (1:5) of lime and sand to stabilize the flues while also allowing for expansion.Image

After this was done I was the able to replace the chimney caps. The caps were bedded in using a strong mix of limecrete. The other option was to use concrete for this and some might say in this instance it may be better but I decided against that.

Next I applied the 5 mm scud coat. This was mixed 1 part NHL 5 to 1.5 parts sharp gritty sand. This has been allowed to cure for 7 days and was sprayed everyday with water.Image

Rained off!

The blasted weather here! Well plenty to do inside. One of the timber lentils over the hall window is seriously sagging because of dry rot.This could interfere with the wall plate if it were to sag later on so I may as well replace this now.Image

All that was involved here is propping the stone work by means of an acrow prop. The the rotten timber is taken out and replaced. In this instance the timber is bevelled to allow for the angled sash window architrave. In the next photo you’ll see just what causes such damage to timber.The scourge of Woodworm!Image

If you look closely you’ll see the little bugger.I’ve found a great You tube video which explains woodworm in detail. Prizon House in riddled with it.

All cement mortar which was used to re-point the stone work at some stage has to be taken out and replace by NHL3.5.Here the finished product.Image

The Chimneys

Welcome back. Hope the week went well for you all. I think overall I had a successfully week having started the reinstatement of the chimneys.

To attack the chimneys in an organized and safe manner I decided to strip back the blue bangor slates starting with the ridge cap (1985 concrete) and working my way down. This would leave room to build three 8×4′ scaffolds each side of the chimneys..This would give great access to the chimneys and also achieve another crucial aspect when wanting  to use lime mortar successfully.

Stripped back slates

This week saw spurts of intense sun, strong wind and rain. Lime mortar must be protected against these elements. Strong sun and wind would dry out the mortar too quicky leading to small cracks and eventual failure.

This Protection along with the use of a Hessian drape will insure the proper curing time. Hessian cloth is a thick woven fabric (Farmers used it for packing wool if Im not mistaken?) that is hung alongside the plaster work which is kept damp. This creates a humid environment thus insuring no excess water evaporation from the plaster work.   With that done it is time to work on the chimneys themselves.  There was considerable water damage. The chimneys were re-plastered I think in 1985 with a cement plaster. In an old house this is a no no. It stops breathability and when eventually water does make its’ way in it is trapped and causes all kinds of problems. So this must be taken off. The mistake to be avoided here is simple but it can be over looked by a novice. Walls in old houses are usually very thick and can withstand a relative amount of vibration but as you move up to the chimneys the wall becomes very thin. This means no mechanical removal of the plaster! All must be done by hand with great care. Restoration is for the patient.  When  all the plaster is removed any decayed material ie. lime mortar joints must be removed. Recess the joint back around 15 – 20 ml. It is important not to remove any joints that are not decayed. This would undermine the stability of the structure.

I decide to wait untill the raking out was finished before removing the brick capping as I though the chimney would remain more intact this way and it worked out fine. Next I removed the brick capping which was very decayed.

 On consultation with the architect it was decided to use NHL5 lime mortar to re-point and rebuild the chimney. NHL 5 is eminently strong while still maintaining a level of breathability. Before re-pointing can begin the chimney must be dampened. To achieve this I decided to hose it down throughly and leave it for a day. This also removed any loose debris. It is important to note while you want the surface to be damp to aid keying you must not have the surface saturated. This would lead again to failure. Tip: After re-poining is finished do not brush the joints like you would when using cement. Use a hand brush and strike the lime pointing in a compacting manner. This should be done when the jointing has stiffened somewhat. This leaves a breathable surface while insuring the jointing is well compacted. Here now is a picture of the weeks finished works. Any comments, questions or critiques feel free!

Ready for capping

Prisone house Balla, Co, Mayo Restoration.

Impossible to date but very old.

Hi all. Before I start let me say I’m a dyslexic bricklayer with a degree in physic who happens to have a love for restoration but who’s spelling is awful and for this I apologize. The reason for starting this blog is to document and discuss the whole restoration process from start to finish. I find it hard to get detailed step by step information on restoration techniques so I’m going to give them to you as I we go through the project. I have a moderate level of experience and I’m working with a conservation architect who’s knowledge of Lime Mortar is exceptional and she also happens to be very easy to ask a question of. Thanks Gerry! It would be great if other professionals in the restoration gave their opinion on project even if were to point out mistakes or alternatives.

The first step in this process was to complete a bat survey and get the go a head.

Our first project is to re-roof the main house. Re-roofing the house has many elements to it. The first is the chimneys. I’m estimating this will take 3 weeks and I’ll be discussing it in detail.

till the next post