What problems are hidden in your roof?

15th October 2014

So many of us tend to pay little or no attention to the roof over our heads. If there isn’t water pouring in through the ceiling, there’s no problem, right? Unfortunately that’s not always the case. There are a some issues that will not become apparent by the influx of rainwater. Dry rot, woodworm and even wet rot can occur with no obvious symptoms in the rooms below.

Brown Rot (Commonly Known As Dry Rot)

  • What causes it – Dry rot is caused by a species of fungi which digest the parts of the wood that give it structural integrity, without an apparent source of moisture. Dry Rot fungi doesn’t need much water to grow, but it does need some, so if you have spotted any Dry Rot in your loft, chances are there is some water getting in somewhere as well.
  • What does it look like – Wood affected by dry rot turns a dark-brown colour and appears to be very crumbly. The wood cracks in square-like shapes and is very brittle and very soft to the touch – like this
  • Is it a big / common problem – From our experience, Dry rot in Bristol isn’t very common, however, unchecked Dry Rot can, over time, become un-treatable and the entire roof frame may need replacing, so it’s best to be sure.
  • What can I do about itBarritine Wood Preservative is a spirit-based wood preserver which treats Dry Rot effectively. The treatment would be best applied with a brush to all roof rafters, even if Dry Rot has only been spotted on a small number. Be aware that some wood preservers do not include protection from Dry Rot.


Woodworm Infestation

  • What causes it – Woodworm is a term given to juvenile form of a wood-boring beetle which causes deterioration of wood. The beetle needs the wood to be fairly damp so woodworm will more likely be found if you have a leaking roof or a roof space lacking in ventilation. It can also be found in wood in other parts of the house suffering from excess damp.
  • What does it look like – Here is an example of a ‘woodworm’. Following an infestation the wood will have many small holes and may be a bit dusty and soft to touch.
  • Is it a big / common problem – Woodworm seems to be more prominent from the roofs we have seen in the area, though it seems to be common for the woodworm to be no longer active, and the damage level is often not alarming.
  • What can I do about it – Woodworm can be treated in the same way as Dry Rot. Many wood treatments like Barritine Wood Preservative include Woodworm treatment. In fact, most wood treatments will effectively treat Woodworm, both active and no longer active and can even prevent it from occurring in the first place.


Wet Rot

  • What causes it – Wet Rot is essentially the natural decay of wood with high moisture levels present. Severe damp lofts or roof leaks will all contribute to wet rot.
  • What does it look like – Wet Rot looks like your common form of wood rot. Assuming there is an ongoing problem the wood will likely be damp or sodden and very soft to the touch. There is often staining of the wood where water has been, it may have signs of mould and will likely smell of the same. Here is an example of Wet Rot. Notice that the Rot will not tend to spread further than the wet area.
  • Is it a big / common problem – Wet Rot will be an issue almost anywhere where wood and water meet for any significant length of time. Although this seems like a bad thing, actually Wet Rot is very predictable and due to its need for quite a lot of water, it is less likely to go unnoticed.
  • What can I do about it – The same timber treatment can be used to treat Wet Rot as previously mentioned. More important though, is to keep an eye out for damp / wet areas in your loft space, as Wet Rot will rarely begin without a generous and continual supply of water.

The common problematic factor for all these hidden issues is the presence of water and a fairly long period of time. None of the above happen overnight and the good news is, if you check your loft-space every once in a while you shouldn’t stumble upon any nasty surprises. You don’t always need to be a qualified roofer to spot a problem. Keep an eye out for damp patches, staining on timber that reveals where wood may have been damp in the past, any odd smells should be investigated further and if you can, try checking during a heavy downpour. Try knocking on the rafters (like you would knock on a door), if they feel or sound soft, weak or crumbly – you may want to get someone round for a closer look.

Treating the roof timbers yourself, even if you don’t have any problems isn’t a bad idea either. It will protect the timber in case of any water ingress. You’ll still need to keep an eye out for damp in the loft though, water getting in through the roof means it could be causing problems to the wooden battens that hold the tiles on the roof. The treatment we have suggested is not the only one available, there are loads of different wood preserves to choose from.  Remember more expensive doesn’t always mean better, read the tin and make sure you’re getting the protection you want.

Lastly, and obviously, if you’re not sure, get a roofer in to check for you. Most good companies will come out and check as a free service and it shouldn’t take very long.