FAQ’s – Get answers from a specialist cob builder

Frequently Asked Questions

We are a traditional building company specialising in cob, stone and lime restoration and conservation projects. Older buildings can be a concern for their owners or potential owners, so we answer some common questions you may have.

I have damp patches appearing on my walls, what can I do?

If you live in an older property you may get damp patches because the walls have been rendered with a building product that does not allow your property to ‘breathe’, normally sand cement and gypsum. This can cause water ingress. The trapped moisture gradually makes its way through the modern plaster and creates damp patches, efflorescence, and often unsightly mould. In advanced cases, this can cause structural damage so it is best to seek advice.

Top tip: Check that your guttering is sound! We visit a lot of properties where damaged or displaced guttering has caused avoidable damage.

What should I do if my building has been rendered in sand cement and gypsum?

We would always advise the complete removal of modern plasters both externally and internally on a cob or stone building. This will allow your building to expel any trapped moisture and allow the drying process to commence. It will also unveil any possible structural issues which can then be resolved. You can then re-render your property using lime, which is a fully breathable product.

If your budget does not stretch to this, we can talk you through other possible options, which may include partial removal and replacement or if you have a stone or brick structure, repointing with lime may be an option.

Does Earthouse do ‘patching’?

We would never advise patching with lime render on cementitious rendering. The two different materials are not compatible and this can lead to further issues. 

On occasion we may patch lime rendered walls, but this is never ideal and generally not cost effective.

We have not yet purchased our property. Will Earthouse visit the site and advise on potential works?

We will discuss your situation and if appropriate we can visit the property independently, with the estate agent, or meet you on site. If you are able to provide a structural survey in advance we can base our estimate on the information given. 

Can I do any of the restoration work myself?

This obviously depends on your situation. We have had customers who start the restoration process themselves and then ask us to take over at a certain point and we also have customers who will labour on their own project under our guidance. We are open to chatting through the options with you.

How much does lime rendering/plastering cost?

As a general rule, lime rendering is worked out based on the square meterage of a property. However, additional factors may need to be taken into account when we provide an estimate or quote. These may include the state of the existing render, accessibility and/or additional travel costs. The number of coats required and the desired finish also has an impact on price.

Unfortunately removing cementitious render can reveal structural issues which can add considerably to the cost of the contract. You will also need to consider scaffolding and decoration costs. 

Earthouse is VAT registered and charges VAT at the applicable rate.

We will discuss all these factors with you during your initial enquiries.

Can cob, stone and lime render be used in conjunction with modern building materials?

Absolutely! We have a number of projects where traditional building materials have been used alongside some really new modern materials and techniques with great harmony. We have established relationships with local trades and we are experienced in working alongside them.

Can Earthouse help with my plans for a barn conversion?

Yes. We are happy to work with you and the other relevant parties to assist with your planning proposal. You can view our recent Barn Conversion projects here.

Can Earthouse assist with scaffolding? What are typical scaffolding costs?

We have worked with the same fully licensed and compliant scaffolding contractor for a number of years now and we liaise closely with them to ensure that the scaffold is appropriate for the required works. Scaffolding costs can vary according to location, accessibility, and the number of lifts required. A full scaffold roof is an expensive outgoing, but depending on your project it may be necessary and could cut costs in the longterm.

Does Earthouse undertake well restoration?

Yes, but only in our local area.

Can Earthouse help with digging trial observation holes?

Yes, this will be charged at an hourly or day rate.

Will Earthouse work on chimney restoration projects?

Yes. Chimney issues can be frightening, but Earthouse are very experienced in ensuring chimney work is undertaken in a safe manner. We also work with roofing contractors who can provide full re-roofing and specialist lead and zinc options.

Please contact us if you would like to discuss your project further.

Threshing Barn Conversion – Central Devon

The Threshing Barn

Cob Barn Conversion Project

In May 2016 we commenced work on a cob barn conversion. The old threshing barn is located rurally, in the heart of Devon’s countryside. When we began work the building was derelict. The tin roof was failing, thereby allowing water to seep into the cob walls, causing more damage with each soaking; if our customer had not rescued the barn, it would have slowly deteriorated until it crumbled completely.

Crumbling exterior of the cob barn prior to restoration - Earthouse Building Conservation Ltd

Crumbling exterior of the cob barn prior to restoration

So commenced the project to convert the barn into a traditional living space with a modern twist. The plans allowed for a three bedroom barn conversion of the main barn with a modern extension and an attached thatched linhay.

The end result will encompass a mixture of old and new, combining traditional materials such as cob, and specialist lime rendering techniques. The use of glass and metal will create a modern contemporary feel with careful consideration to the surrounding environment.

With a project such as this one there are many elements involved. We work closely with the customer, architect, and various subcontractors on each part of the project.

The threshing barn covered by a temporary roof.

Threshing Barn covered by temporary roof

Removal and repair

The first job was to remove the superfluous tin roof. This in itself an easy job; the repair to the damage its inefficacy had caused, more demanding! The cob walls required extensive repairs. We commenced work on the south facing wall and worked our way clockwise around the building, removing any inadequate cob and replacing and rebuilding with cob blocks and earth mortar. Overall the work took around six months to complete.

The commencement of cob repairs to the walls in the main barn

The beginning of cob repairs to the walls in the main barn

External wall repair using cob blocks

External wall repair using cob blocks

The roof

After we completed the main barn’s cob walls, the oak wall plate was fitted. Four oak trusses, hips and purlins then soft wood rafters were put in place, with the insulation installed between. The insulated felt was overlaid and battens made ready for the first slates to be laid.

The slate used for this project was a natural slate called Glendyne. We used a local company, Kilbride Roofing Ltd, for this element of the project.

Oak trusses in the roof of the main barn

Oak trusses in the roof of the main barn

Partially laid slate roof

Partially laid slate roof

Following the completion of the slate roof, the soffits, fascias, guttering and downpipe details were added.

Slate roof with guttering in place

Slate roof with guttering in place

External Lime rendering

Whilst there was activity on the roof, Earthouse was busy rendering the exterior with a traditional lime render. Lime render allows cob to breathe, allowing moisture to travel in and out of the cob without damaging it. An insulated lime render was used for the first three coats.

External lime render on the barn conversion

External lime render on the barn conversion

Windows

The main barn has two windows of note. Both are floor to roof, a height of 4.5 metres each. The window frame is made from Douglas pine, sandwiched between 80mm of oak either side. Aluminium windows will be fitted.

Window being installed in the main barn

Window being installed in the main barn

Floors

Next was the excavation of the interior floors. Then came the laying of insulation (glapor) and the installation of underfloor heating pipe. The main barn has a cut back pumice limecrete screed, not dissimilar to polished concrete, but with different shades of grey and white tones and a matt finish giving a more subtle look.

Limecrete pour finished

Limecrete pour finished

A closer look at the limecrete floor in the main barn

A closer look at the limecrete floor in the main barn

Modern Extension

The floor in the extension is a polished concrete, which has a beautiful shine when sealed and is more in keeping with the modern element of this part of the building. Again, the concrete is warmed by underfloor heating.

Concrete floor just laid in the extension

Concrete floor just laid in the extension

The extension itself is a single storey lean-to attached to the north and east elevations of the main barn. The external walls and roof are ultra-modern dark grey crimped zinc. We are seeing so many buildings using crimped zinc now.

Commencement of the contemporary extension

Commencement of the contemporary extension

The extension with a crimped zinc roof and cladding and large glass sliding doors

The extension with a crimped zinc roof and cladding and large glass sliding doors

The extension spans two walls of the main barn conversion. It is 50% glass, comprising both doors and windows supplied by Aspect Windows Ltd in Exeter. The photo below shows the far end of the barn conversion, with the extension; these rooms are ensuite bedrooms.

Inside the Threshing Barn

The interior of the barn on completion is large and light. The main living space is vaulted double height, overlooked by a timber mezzanine floor.

Work in progress in the interior of the barn conversion

Work in progress in the interior of  the barn conversion

Upon the mezzanine is the office. Below the mezzanine floor lays a hallway leading to bedroom 3 and the staircase leading up to the floor above. There is also a passageway leading to the ensuite bedrooms 1 and 2 in the extension.

The mezzanine wall in place in the main barn

The mezzanine wall in place in the main barn

Upon completion, the mezzanine wall and timber was painted with Farrow & Ball paint in many different shades of grey. The majority of the lighting is from a fantastic shop in Exeter, Amos Lighting, which we highly recommend.

The woodburner and flue was supplied and installed by Woodwarm near Cullompton, who offer a wide range of contemporary and highly economic woodburners.

The almost completed mezzanine in the main barn conversion

The almost completed mezzanine in the main barn conversion

Wild complications

No project is ever without its own unique set of complications and whilst at Earthouse we are lucky to work in some beautifully remote locations and we regularly see fantastic wildlife, our barn owl invasion was by far the most spectacular.

Midway through the cob repair process of the walls in the main barn, we came across a nest in a hole in the cob containing two young barn owls. We were first alerted to their presence by the malodourous smell, presumably from the owls eating and digesting numerous small creatures. (We had a good rummage through some of the furry grey pellets they had discarded at a much later date with a vet friend of ours who identified any number of tiny mouse and bird skulls and bones!)

The young owlets were snuggled up in the wall which was in the worst state and without attention this wall could crumble, crushing the birds.

Barn Owl chicks nesting in a cob wall

Barn Owl chicks nesting in a cob wall

Barn Owls are a protected species which we were well aware of and we sought immediate advice from The Barn Owl Trust. In order not to disturb the creatures we stopped work until the Barn Owl Trust had visited site and specified where and what we could continue. A temporary owl box was erected closely in the vicinity of their original nest and they quickly took to this, the droppings making their use of it evident.

Many people would be disgruntled by owls stopping work on their site and to a degree it was frustrating. However, the owls enchanted us and the owner, who now has a fantastic extension of a large owl box which the owls began using almost immediately, obviously not concerned by the continuing building works going on around them.

Permanent owl nesting box built into the roof of the house

Permanent owl nesting box built into the roof of the house

Another view of the barn owl nesting box at the top of the threshing barn

Another view of the barn owl nesting box at the top of the threshing barn

Before and after – a drastic restoration project!

The final parts of the project are always vital; the construction is obviously key, but these are the bits that the customer living in their home will see. As I write, the site is once again a building site as work commences on The Linhay, so I don’t have the beautiful landscaped photographs of the finished barn quite yet. Below you can see the stark contrast of the barn when we first started working on it, and the newly lime rendered conversion and extension in the wonderful Devon sunshine.

Interior of cob barn prior to restoration - Earthouse Building Conservation Ltd

Interior of cob barn prior to restoration

Crumbling exterior of the cob barn prior to restoration - Earthouse Building Conservation Ltd

Crumbling exterior of the cob barn prior to restoration

The barn looking stunning in the sunshine with a tree-lined backdrop

The barn looking stunning in the sunshine with a tree-lined backdrop

View of the barn conversion and extension

View of the barn conversion and extension

The owners spent Christmas in their beautiful barn conversion and we hope to have more interior and exterior photos to show you very soon.

If you would like to know more about the work we do, or to discuss your barn conversion project, please feel free to contact us.

To be continued…The Thatched Linhay