Period Oak Truss Restoration, Your 5 Step Guide
Existing oak trusses can, in my opinion, end up making a room within a period property look incredible – or can end up just becoming an “epic fail” if not restored properly.
I’ve seen the restoration of oak trusses done badly far too many times and want to help enthusiastic period property owners and lost builders to find the right path to success.
Step 1 Existing timbers
You need to appoint a decent and confident carpenter/joiner to cut out any of the existing rotten or soft wood sections from the truss and replace using new timber to match the existing. More commonly than not, you will find that your trusses will be made using English oak from the UK.
Unfortunately, due to the local authorities slapping Tree Protection Orders on most of our established oak trees in the UK, you will find that the price of English oak is very expensive in comparison with European and French oak. Our American cousins produce an oak (cleverly labelled as American oak) which is very white and is the cheapest oak on the market.
I have taken oak as an example here, but it’s important to match your timber correctly, because if you replace any sections with a different wood, it will simply stick out like a sore thumb.
Once you have removed the defected or incorrect timbers, they will need to be replaced, ensuring that the existing marry properly and that the joints and connections are scarfed properly. One common fault is to try to fill between the two timbers. Seeing this makes me want to cry and should never happen – it is simply a disaster.
A good joiner will need to replicate the existing junctions, for example a mortise and tendon joint.
Step 2 Sand Blasting
This is a must. Many people (including other contractors) cannot believe that we actually sandblast our “old” timbers, but I’m telling you, there is no better way to bring them back to life – the rich and chalky colours that are hidden inside really come out. Most people associate sandblasting with graffiti removal, but using the correct grade sand and a consistent, experienced blaster, it really works.
I always ask my sandblaster to do a small test patch in a corner out of the way or even on the off cut of timber you have just removed before committing to the entire truss. Using a sandblaster may sound expensive as opposed to a decorator using a piece of sand paper and elbow grease, but there is no comparison with the finish. Remember though, sandblasting is super messy so prepare for sand everywhere!
Step 3 Treatment
It’s very important to treat the timbers and twice saturate with an anti-dry and wet rot system. Obviously you should have already cut and removed any existing rot, but this treatment will ensure the rot has gone completely. There are many types of treatment systems on the market and I would recommend using a system that carries a decent 10 year recognised guarantee.
Step 4 Adding Extra Period Features
This is now your opportunity to jazz up the truss and add features such as pegs and bolts, washers and brackets. Always ensure that they are suited to the period of the property and are added within the correct locations. For example, you wouldn’t want to put a medieval candle holder in a modern piggery.
Step 5 Treating and Decorating
As with the sandblasting, I recommend doing a few test panels before committing, but generally, I like to use a clear, very good quality varnish. Lots of decorators will tell you to just add one coat, as that’s all it needs because it’s now sealed. This is incorrect in my experience – the second coat improves it and the third really brings the truss alive.
I hope this serves as a useful guide for restoring a period oak truss. As you can see, it is a process which requires care, attention and expertise in order to be done properly. We are lucky to work with a team of exceptional contractors who all firmly believe in doing things the right way, and who will not compromise on the quality of the restoration work by cutting corners at any stage of the process.