Advice sought: Main beams, repair or replace?

[Moorhouse]

Hello everyone,

I’m new to the forum and this is my first post. My name is Kenny and I’ve recently purchased an old cottage near Bristol which is estimated to be around 150 years old. It’s been interesting reading through past posts and I am hoping that someone will be able to help me with some advice on our next steps. I’ve included a few photos for reference.

The property is not listed and had been used for social housing for the last 60 years where the tenants undoubtedly loved living there but the maintenance of the property was the responsibility of the housing association who did little to care for, or preserve the character of the property.

As a result the property has been affected with damp and woodworm of sorts. This was identified during the survey but the extent of the damage wasn’t known until the sale was completed and we started investigating. There is evidence of woodworm throughout the property although this could be historic as there is no obvious signs of it still being active. There have been remedial repairs over time, none of which seem to be sympathetic to the property.

The first floor is composed of several large beams which span a 4m gap (1). All of the timbers which run adjacent to these beams have damage from woodworm, with the most severely affected being almost hollowed out (2). I had hoped that the extent of the repairs might be to replace these timbers but I fear that may have been naively optimistic as where the large beams meet the walls there is more notable damage (3) and one of these beams has been sistered with a modern floor joist (4).

I have had a local builder round who suggested replacing the floor structure with RSJs and modern floor joists but before considering this further, I’d like to explore the possibility of repairing & trying to retain what character is left.

I’d welcome any advice, or if anyone can recommend an appropriate tradesman in the South West of England who could undertake an assessment and the work that might be required?

Thanks for taking the time to read this.

Kenny

 

[fernicarry]

I’d like to explore the possibility of repairing & trying to retain what character is left

What is it you want to keep? Do you want to expose the main beams?

You've already lost the historic bits like the lathed ceilings, floor boards, skirting boards, fire surrounds. Some of the wall coverings look like plasterboard with gypsum skim. Not really much original left tbh.

Maybe take the opportunity to strip it right back and rebuild the interior to a good standard of thermal performance?

 

[Cubist]

Hi Kenny and Welcome,

I admire the ambition and you seem to have a good grasp of the important issues your home is facing. Key and critical among these is the structural integrity of the bressummers linking the front and rear of the property and the joists carrying the flooring. All/many of which appear to have suffered considerable damage due to damp and beetle infestation over the years. Its not surprising that where the bresssummers enter the external walls that you have found some of the most severe damage - the end grain of any timber is the greatest point of vulnerability to water/moisture incursion which in turn encourages the beetles. You don't mention the exterior finish of the cottage but poor choices such as render coatings in the past may have contributed much to the problem.

The brssummers may be salvageable depending on their overall condition and structural integrity but it may be necessary to either replace them completely or, if the damage is limited to a shortish length where the timber sits inside the wall, the rotten material can be excised and replaced. The damaged joists may also be capable of repair but again much depends on their condition and physical integrity. Whist the photos you have provided are helpful only on-site examination can finally confirm just how much of the timbers can be saved.

I'm sorry, but either way this looks like an expensive job and one, particularly if you go down the route of saving what you can and perhaps need the assistance of some of the rarer skill sets among the building community, then it may also take much longer than might otherwise be anticipated.

Happy to provide what help and advice I can and there are other members here who have faced similar challenges and willing to offer opinions.

Good luck and stay in touch.

Cheers, Cubist

 

[Zebra]

In a similar situation I replaced the most damaged joists, maybe 10% in my case, not with timber from the builders merchants, but with green oak from a woodyard, in a size to match the original. I then used the best bits of the removed ones to repair others - a new end where one was short. If they were structurally OK I left them.
I had taken the laths down as you have, which I perhaps regret from a conservation point of view...they were original...so in the end I reused them, cut them down and screwed them to battens screwed to the sides of the joists and lime plastered them, revealing the joists which had been covered previously.
Where you have a wet beam end in the wall, tackle the issue with the damp in the wall. The beam end looks OK.

 

[Moorhouse]

Thank you for the replies.

If possible we'd like to keep the exposed beams in the kitchen and living room so it is encouraging to hear that repair isn't out of the question even if it comes at a cost. As you say Cubist an on-site inspection by someone with expertise is really what's needed.

Do you know what the approximate cost of replacing one end of a bresssummers might be & are these repairs done in-situ or is it removed first? I realise there are a lot of variables so just a ball park figure would be a start. If anyone in the South West that has employed someone to do this I would really appreciate a recommendation.

I'm probably at risk of forum blasphemy here but are methods such as sandblasting and sanding appropriate where you want to remove the surface damage (from woodworm) in order to reveal the extent of the damage to these large beams, or is there a more appropriate way to assess this?

Cubist "You don't mention the exterior finish of the cottage but poor choices such as render coatings"
Lots of poor choices here which have undoubtedly affected the health of the property over years ; rendered, gypsum plaster, inadequate heating, ventilation, drainage & poverty.

Just saw your reply Zebra (thanks) which is what I envisaged doing at the outset and I’d consider to be a good outcome.

Cheers Kenny

 

[Cubist]

Hello Kenny,
Speaking personally I am pleased that you want to save the extant timbers as far as possible but you will need a timber framer who has the necessary skill and experience to make the needed repairs in as sympathetic a manner as possible. The issue here is that these timbers have the two structural roles of binding the outer frames together and supporting the 1st floor and ceilings below. The repair would require the removal of the rotten timber and splicing in a new section to replace it BUT the new joint has either to be strong enough to withstand the loads that may be exerted by the first floor and its contents or additional support in the shape of a column/post positioned near to the joint must be installed. You really do need to talk to a good framer who can provide you with written references regarding their work.

Regarding the surfaces of the timbers. Bluntly, I would not use any aggressive means to remove the woodworm evidence as, quite simply, you would be literally 'opening a can of worms'. The woodworm may have been active in the timbers for anything up to 5 years and will have created a vast network of tunnels through the wood. Sanding and particularly blasting, will bring those tunnels to the surface which will present themselves as a map of the beetles activities and destroying the final appearance of the timbers for all time - DO NOT DO THIS please. Professional furniture restorers will sometimes inject a suitable expanding glue into the surface holes to fill the tunnels and to help restore some of the woods strength - Toby Newell, a member here may be able to offer some direct advice on what products and techniques may be most appropriate.

Cheers,
Cubist

 

[Toby Newell]

Professional furniture restorers will sometimes inject a suitable expanding glue into the surface holes to fill the tunnels and to help restore some of the woods strength - Toby Newell, a member here may be able to offer some direct advice on what products and techniques may be most appropriate.

mmm, thanks for the mention but as the Aussies say, yeh nah

I am not a framer, nor a pest expert, and I defer to, I forget his name, but I believe Middi might be or have been a framer and one of the Matts, who I believe is a pest expert.

Having said that, I have repaired several hundred suspended floors and I guess maybe two or three dozen basket cases, including maybe a dozen or two Georgian / Queen Anne / Tudor floors with waney edge (mostly oak but occasionally elm, birch or pitch pine beams / joists such as yours.

Whilst I am one of the most vocal advocates against blasting of any sort (I have managed, somehow, to survive 38 years of stripping several thousand sqm and tens of linear km of timber without having to do any sort of blasting) that is for exposed beams.

For floors, and this is just my personal opinion (I am a very advanced amateur that makes it up as I go along) I generally scrape off as much friable material as possible.

In the majority of cases (think of a bresummer beam for example as a long sausage roll) it is mainly the softer, creamy coloured sap wood that looks and acts like flaky pastry.

Filling this is pointless imho, it's not just a case of filling the holes, the holes are simply a symptom (worm infestation) of the cause (prolonged damp) and prolonged damp will turn sapwood into flaky pastry. Filling the holes will just mean you have flaky pastry with no holes... this is ok on floor boards because you can put a ton of hardener and filler in to stabilise and the timber will not move.

However. It would still not be strong enough to be load bearing.

I am a furniture restorer and I have worked with hundreds of French polishers and I have never seen any one of them using an expandable glue to fill worm holes, that is not say it isn't done, just thst I have never seen it. In fact, rarely would you fill worm damage on a period antique as it is part of the patination and would be a bugger to colour out. The most you would normally do is treat if required with a hyperdermic then fill (if requested) with wax beaumontage.

Instead I hack off until I reach the sausage 'meat' core, which is the super hard chocolate coloured heartgrain. This is normally unaffected or just has a few galleries.

Sometimes I will let in a bit of timber to straighten up the side to facilitate the fitting of noggins.

Very rarely will the heartgrain be badly riddled with holes, if it is weak and friable the obviously the timber will need to be replaced.

I have removed and replaced entire structures with 6x6" timber on v small floors and augmented damaged beams on several occasions without having to remove or prop anything, including stabilising damaged bresummers.

However, I would draw the line at removing a bressumer and replacing as that would require support and careful planning.

Just FYI, for surface timbers eg flooring, pretty much any level of damage can be saved. I use a combination of wood hardener, followed by self coloured two part polyester filler and / or two part epoxy adhesive filler and resin and sawdust. I stabilise further by adding a penetrative finish like shellac, followed either by wax or lacquer.

I never use expanding foam or even expanding glue (PU type 'Gorilla' glue is a lower foaming moisture curing PU almost dentical to expanding foam)

To me it just seems obtuse. When I stick things together the strength of the bond is directly proportional to how close the surfaces are (super flat metal spontaneously cold welding to itself) and an adhesive / filler that pushes the joint apart?

I use CA glue (2 part w activator) for small internal cracks, along with D3 PVA if I can leave clamped for a day, hybrid MS polymer glue for stronger sections / noggins / fillets / shims / boards / sistering (technically its not a structural adhesive, but the high tensile ones pretty much are, although there is a vast range of strengths and it took me months to research!) and for supermax structural the 2 part epoxies which pretty much are the strongest adhesives available.

So, to be as obtuse as possible, yes I would hack off and no, I have never and would never use any sort of expanding filler. Although to be uncontrarian for a moment I am 100% anti blasting, of any sort, for anything but sound hardwood, which will always need further sanding after the fact.

French polishers' Kryptonite is pledge. A conservator cum wannabe framer like myself, it's squirty foam, so I have two.

As a final aside, using squirty foam outside in thin film makes for a great outdoor adhesive as moisture cured PU has great waterproof properties, if you don't mind the clean up.

 

[Toby Newell]

Hello everyone,

I’m new to the forum and this is my first post. My name is Kenny and I’ve recently purchased an old cottage near Bristol which is estimated to be around 150 years old. It’s been interesting reading through past posts and I am hoping that someone will be able to help me with some advice on our next steps. I’ve included a few photos for reference.

The property is not listed and had been used for social housing for the last 60 years where the tenants undoubtedly loved living there but the maintenance of the property was the responsibility of the housing association who did little to care for, or preserve the character of the property.

As a result the property has been affected with damp and woodworm of sorts. This was identified during the survey but the extent of the damage wasn’t known until the sale was completed and we started investigating. There is evidence of woodworm throughout the property although this could be historic as there is no obvious signs of it still being active. There have been remedial repairs over time, none of which seem to be sympathetic to the property.

The first floor is composed of several large beams which span a 4m gap (1). All of the timbers which run adjacent to these beams have damage from woodworm, with the most severely affected being almost hollowed out (2). I had hoped that the extent of the repairs might be to replace these timbers but I fear that may have been naively optimistic as where the large beams meet the walls there is more notable damage (3) and one of these beams has been sistered with a modern floor joist (4).

I have had a local builder round who suggested replacing the floor structure with RSJs and modern floor joists but before considering this further, I’d like to explore the possibility of repairing & trying to retain what character is left.

I’d welcome any advice, or if anyone can recommend an appropriate tradesman in the South West of England who could undertake an assessment and the work that might be required?

Thanks for taking the time to read this.

Kenny

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pics 2 and 3 do not look super fantastic.

hard to know what to say without knowing what picture refers to what.

In general you certainly do not need to throw everything away just because one or two timber are badly damaged.

But then I am a conservator and not a builder.

Hence builders like to build, not conserve, which is a lot easier, because you just hulk smash and replace, whereas conservation is a right pain in the prefontal as you constantly have to think and innovate.

So, I don't necessarily blame builders, as long as they are honest, ie let you know that yes, someone could probably repair and save most of your structure, but that's not going to be me mate! Which, to be frank, is a sign of intelligence.

The only beef I have is when they say saving is impossible, rather than too much bother for most sane men, which may be a perfectly reasonable view to hold.