Rebuild or repair?

[saveasteading]

A big dilemma.  Repair or rebuild?

The steading has four sides, with a central courtyard that used to be a cattle area. Three of the wings are unusually solid and require only local repair.

The fourth, rear wing is another matter and it is for that I seek your learned thoughts.

There used to be a roof over the central area. This was presumably a later addition as was the custom in the area, when cattle became a bigger earner.

This canopy was in an awful state, so we have removed it. Already the building is in better order re damp and the leaning of broken timbers.

The canopy has been pouring water from its valleys onto the poor rear wing for decades, washing out mortar and causing some failure of the walls.

 

If there was no roof, it would be obvious that the walls be completely removed and rebuilt.

However there is a watertight roof, with 95% of the timber in good condition, as are the sarking boards and as is the slate. However to one length of about 10m at the courtyard, the wet has rotted the bottoms of the rafters, the roof has dropped (and rotated?) and rain runs on the walls.

 

If the walls were solid, I think we would jack up the roof trusses, splice on new ends where the bottom has rotted, and lay it down again.

Then, concurrently or later, we would remove the dodgy areas of wall and form new openings, retaining the footings and lower layers, and rebuild.

 

BUT with some damaged timber and some broken/leaning  walls the local builders all want to take the whole roof and walls down, and rebuild with new materials (They have not the slightest intention of re-using the timber. I think this is because it needs de-nailing and more thought.)

The new timber will be about £5,000. I can’t see them being careful with the sarking either so add another £1,000.

Strip slates and sarking, cut off roof and dismantle stone walls, rebuild both with new materials wood/ concrete block (to later be timber clad)

 

In my estimation we are comparing a £5 to £10,000 rebuild, with £50,000 new.

 

Against which is the risk that my idea might not work…quite, or be a shorter term solution.

 

Perhaps I am being overoptimistic, or perhaps the builders don’t acknowledge anything out of the ordinary.

 

From inspection of all junctions/ movement etc and some old photos, I don’t think things have got much worse or moved for many years. I am a Chartered Engineer by the way, and would not do this lightly. But this is a new sort of building to me and there may be problems I haven't thought of.

 

If removed, will the Building Inspector require modern calculations, or will he accept my view that it has done rather well for 140 years and can perform again, by inspection?

The roof as it is would be impossible to prove to current standards, which would require a lower tie I think, to prevent outward thrust. However, for either way forward, I plan to make every new cross  wall as a bulkhead, using plywood fixed to the rafters for strength, and some diagonals to link to the other trusses.

Perhaps the ungraded 6 x 2" rafters can be increased to graded, deeper sections.

My other aim is to not remove the whole wall  as we then might have to build as new, with deep foundations, and I don't like new, deep  concrete foundations next to old, shallower  lime ones.

 

 

Photos of the internal area attached . Floor is concrete. Walls are 2.2m high, 600 thick. Roof is A frame with ties  at 3.1m and ridge 5m.

 

 

 

 

[ProDave]

If it is just the lower part of the roof that is affected (i.e. below the ties) can you not prop up the rook on acro's dismantle and rebuild the wall and repair the damaged parts of the roof?  Cut off the damaged parts of the rafters and sister new timber alongside?

[MikeGrahamT21]

Have you been watching the George Clark and Charlie Luxton (C4 and More4)? They've been doing programs about this exact topic. From what i've seen the rebuild costs are always much greater than anticipated, as something always throws up a spanner in the works. 

 

Remember everything has to be to building regs, and they have the final say. That concrete floor is going to have to come up for a new modern insulated slab for a start, i'd bet that will be the best part of £7k there alone.

 

P.S This is assuming you are converting it into a home...

[ProDave]

Re the floor.  A guy near here started converting a steading.  He needed to lower the floor 6" to get enough headroom for an upper floor.  Once he had scraped 6" off the floor (he needed to go deeper for insulation and concrete) he had reached the bottom of the "foundations" that the walls were built on.

 

He ended up knocking the lot down and doing a new build.

[saveasteading]

8 hours ago, ProDave said:

If it is just the lower part of the roof that is affected (i.e. below the ties) can you not prop up the rook on acro's dismantle and rebuild the wall and repair the damaged parts of the roof?  Cut off the damaged parts of the rafters and sister new timber alongside?

I think so, but would have to persuade a builder the same. Unfortunately I cannot be on site to supervise, and my family there are torn between my views and the various builders met so far.

We have even bought some hydraulic acros for the purpose, so we can nudge it back up to height.

I have seen a roof exactly as you described in a local hptel, recently rebuilt.

[saveasteading]

8 hours ago, MikeGrahamT21 said:

that concrete floor is going to have to come up for a new modern insulated slab for a start

Not so, fortunately. The Scottish requirements are to insulate towards reduced insulation targets 'as far as reasonably practicable'. That includes cost, but in our case would also cause headroom problems.

 

AS ProDave says, breaking out the floor could compromise the building. A local builder* has also confirmed this as being a known problem, so I expect building control to be aware. Otherwise I will be asking urgently on here for details and locations.

 

* he also mentioned (as I had surmised already) that sometimes foundation stones project into the building space, so can be disturbed during the breaking out.

Another builder said that ''obviously' you can't keep the old slab', which only tells me how little the designers he has worked under know about structure and cost.

 

8 hours ago, MikeGrahamT21 said:

George Clark and Charlie Luxton (C4 and More4

I must find this! any more clues about location so I can search for it?

 

Re the cost, among my hats is that of Estimator, so I did a costing before we committed. It is a lot of money. So far there have been savings but there are issues appearing all the time. Commercially I would have added 10% for unforeseens, (and that would not be enough if not watched very closely) but the family vetoed it. 

I am used to designing my way out of problems, where many others throw money at it.

Hence, if we can spend 10k on resolving the big issue here, instead of £50k or more) we are close to target still, and 3 months faster.

 

May need proof though for the family first , then for builders who will do as told.

 

 

Building control seldom have the final say with me , unless it is approval. Have had many a stand-off ( really only 10 times in 300 projects probably, but I remember them well) and usually find that they don't know the rules anything like as well as they like to think.

The good ones agree professionally, the weak ones reluctantly. Sometimes I agree with them, or am happy to modify to tick a box.

In this project a lot is new to me, and so sensible discussion with BCO will be welcomed.

[MikeGrahamT21]

They’ll definitely be on channel 4s streaming service. All ones I’ve seen so far have been in England, but may still be useful.

[Hastings]

One of my roofs was in a similar state of repair to yours, it sounds like, and I really wanted to avoid total replacement but was advised that a new roof would not be much more expensive than repairs followed by regular ongoing repairs. When I added on the peace of mind factor (lying awake at night listening to the wind) and personal time and 'cost' of dealing with ongoing repairs I felt that argument was right for us. But we are exposed coastal. No trees for miles. New trusses also provided the basis for the upper floor ceiling thus helping with the new internal timber frame walls build. Mine is a 2 storey building which makes the argument for spending more on the roof stronger than if it was a single or half storey like yours. Greater costs for me were in repairing the chimney breasts (you have none) and two of their flues, replacing all stone lintels (mostly all cracked) and timber lintels with concrete ones (4 or 5 per opening).

 

My roof turned out quite inexpensive but it has no hips, valleys or dormers or lights.

 

With your steading, if you keep the floor, raising the level with insulation, you might need to raise the door/window lintels too? Some look very near to eaves wall plate height already. If you do a new roof you have the opportunity to perhaps raise the walls and roof a little.

[Cpd]

26 minutes ago, Hastings said:

If you do a new roof you have the opportunity to perhaps raise the walls and roof a little.

This is what I did, floor needed raising so I dug down as far as reasonable and then made up the shortfall by adding on a bit at the wall heads, I believe that it will be cheaper to keep what you have as your roof is large and complex where as my roof was small and simple. 

[saveasteading]

Thanks. Currently thinking to retain lintels, even where cracked, by forming steel subframes which will suuport and also  square up for windows.

Re height, planning to have lobbies at current levels with minimal insulation and screed,  then step up to new floors.

V keen to find a solution to avoid a new roof. I agree with ProDave that it can be kept, but the family not convinced. I am the Engineer, but they have to live there, and builders need to be persuaded. 

[Gus Potter]

On 26/08/2021 at 23:57, saveasteading said:

The roof as it is would be impossible to prove to current standards, which would require a lower tie I think, to prevent outward thrust. However, for either way forward, I plan to make every new cross  wall as a bulkhead, using plywood fixed to the rafters for strength, and some diagonals to link to the other trusses.

 

Can you turn the cross walls into load bearing walls? It already sounds like you are intending that the cross walls should provide lateral stability to the external walls. i.e they are shear walls. Build these in timber frame if you like.

 

Roughly where the ceiling ties join the rafters can you stick in a purlin running in the direction parallel to the long walls? The purlin is supported on the cross walls. The purlin can sit above or below the node point to the ceiling tie / rafter. These purlins take out all the spread out of the roof and carry the majority of the vertical load. Not you have relieved most of the load off wall that is causing problems and you can work on it as and when you like. It's (the ropey wall) pretty much left to carry it's own self weight and a small portion of rafter load from the bottom two or three feet of slates / sarking.

 

The same principles can be used for loft conversions where the roof is required to carry heavier loads. This may work fine or you can often adapt the principle to suit the layout.