Dry Rot & Damp (worried FTB)

High_Roller_2

Hi all,

I'm a First Time Buyer and need some advice. I'm buying a lower-ground floor flat where the front of the property is partly underground (window is at street-level) and the back is like a standard groundfloor flat providing access to the garden.

The survey was carried out a couple of weeks ago (Homebuyer) and it was advised that I should get a damp specialist in prior to completion to assess the severity.

The damp specialist went in at the weekend and found two problems:
1) Dry Rot in one of the inner walls. I understand this can be a serious problem? They've quoted £2,300 to sort this.
2) The second problem is damp and they recommend various treatments including tanking 2 walls and injections into some other walls. The quote for this is £1,700. I thought that tanking would cost more than this?

Is dry rot a deal-breaker? I'm less concerned about the damp, but am I right to be? The damp seems quite widespread. The company that went in are Kenway, if anyone has had dealings with them it would be great to hear your experiences. I should note that it was the EA that recommended them to me (not the smartest thing I've ever done)

Thanks

poppysarah

Could you buy a property without the problems?

The problem with damp is things can end up being a lot worse when you start uncovering. Get them to do the work or walk away.

marcg

As an architect, I say walk away.

Dry rot is a fungal infestation - it is treated by spraying and the work will be guaranteed for a period of time. BUT if it comes back you'll need to move all your stuff out and they'll have to rip out any protective layers (such as plasterboard or carpets) and spray it again. Whether the work to make that right again is covered by their guarantee depends on the company.

Below ground damp is a never ending story - the reason it exists is because the water table is higher than the floor so there is constant water pressure on the outside of the wall - the same as at the bottom of a well or when you dig a hole in the sand at the seaside. If I was starting from scratch I'd dig a big hole all around the base of the building, put a drainage channel at the edge of the building and backfill with gravel so that all the water is carried away from the building. When the building is already there and you can't dig up the pavement that only leaves two choices - let the water come in then drain it away once it's in (by building a false wall in front of the original wall and draining the cavity) or by "tanking" which is applying or painting on a plastic membrane to hold the water out. Given that there is a constant pressure of water on the back of this trying to force it off the wall, tanking doesn't usually last all that long.

For goodness' sake; it is a buyers market, find somewhere else!

HAMISH_MCTAVISH

I've dealt with both problems before for my retired parents house.

In a 400K house, the costs of around 7K were worth it.

In a 100K flat, not so much.....

Theres lot's of choice out there, and you'll never see the money back. If you proceed, tell the buyers to pay for it or take it off the price.

Running_Horse

Remember, most timber and damp guarantees are not worth the paper they are printed on. They are good to wave at a potential buyer, but just try claiming on one.

High_Roller_2

poppysarah wrote: »

Could you buy a property without the problems?

Probably, but it's taken me 5 months and 30+ viewings to find this one. During which time I found one other that I liked and had an offer accepted but I got gazumped :mad:

poppysarah wrote: »

Get them to do the work or walk away.

marcg wrote: »

As an architect, I say walk away.

HAMISH_MCTAVISH wrote: »

If you proceed, tell the buyers to pay for it or take it off the price.

Thanks for the advice, I won't be sleeping well tonight!

High_Roller_2

Thanks Running Horse, I can imagine they're tough to follow up on!

The previous damp proofing and dry rot work guarantees expired a couple of years ago, but as you say that's irrelevant.

I just want the peace of mind that I'm moving into a property that will stand for a good few more years without being a money-pit.

David_Aldred

Hello High Roller,
The direct answer to a direct question of whether I would buy a property with dry rot is no I would not, simply because dry rot is fortunately rare and once the fungus becomes embedded within the fabric of the building it is impractical to remove entirely, so it currently being a buyers market opt for the majority of properties that do not have dry rot as opposed to the few that have. Don't forget you will have to declare the history of dry rot to any future purchaser when you come to sell and just as now such history makes the property hard to sell which is another reason for not buying in such a fluctuating market. Your question did raise quite a few issues so the following more in depth general comments may prove useful for your info though they should not be relied upon for specific cases. The first comments cover dry rot - the second dampness below ground level.

Dry and wet rot spores are present within the air all the time, that is to say they are ubiquitous and only require certain conditions to be met to promote rapid colonization. Primarily both wet and dry rots require oxygen, water, a certain temperature range and a food such as timber or timber based products. In a property where wood is plentiful the only thing that can be realistically controlled is the water and if the moisture content of timber is kept generally below the threshold of decay (20-22%) the decay will not occur, or if it has previously occurred due to some moisture being present, if the moisture is removed to a level below 20% the decay will die out irrespective of chemicals that may or may not be used as support measures.

Dry rot is sometimes called a cancer in buildings and it is quite a clever fungus in that it can transport moisture along its strands and wet ahead of itself to turn timber that was previously dry to an appropriate state of wetness so it can continue to feed on more wood and promote its own growth. It does not feed off masonry or soil or weak solid floors but is known to grow through such areas searching for more timber to feed from and hence if it grows through a party wall it can be a nightmare to control if one owner fails to address the fungus on their side while you are doing your best to resolve it on your side such that it keeps growing back through the party wall into your dwelling.

Once embedded within masonry it cannot without rebuilding be fully removed in all practicality. The primary control measures are to address and remove the moisture source feeding the decay, to reduce the moisture content within the timber where retained, to below the threshold of decay and where possible isolate / remove timber which is the food for the fungus from infected areas. At one time people used to blowtorch the fungus where visible but this had limited effect and house fires as a result is the obvious risk amongst others. Fungicide chemicals can be used more effectively but only ever as support measures to the primary measures mentioned above and never as a substitute. Indeed some people are totally against introducing chemicals at all especially as with hindsight many that were once in common use have now had to be withdrawn because they were linked to cancers etc. Where chemicals such as borons are used as support measures they should be limited to protecting timbers considered at risk that cannot be removed from the infected areas during the drying down phase. The rule of thumb as suggested by the Building Research Establishment (BRE) for in-situ treatment of adjacent sound timbers is if the timber can be dried down to below the threshold of decay (under 20%) in under eight weeks no chemical treatment is required. If drying down is going to take between eight weeks and six months apply remedial preservative to the area affected and in the case of dry rot consider isolating any retained timber with masonry fluid. If the drying down is going to take longer than six months isolate the timber from damp masonry or replace with material the fungus will not eat such as steel / concrete.

Trying to sterilise a full wall with fungicides is unlikley to be completely effective and the aim is to dry the area down not make it wetter with water based products, so to reduce this issue pastes and solvent carrier chemicals are preferred where walls are irrigated with fungicides. The hassle as I said before is the fungus will remain in the fabric of the building after treatment and if conditions become favourable at some point in the future or as often happens are not fully resolved at time of treating the infection it may well come back to haunt both the client and those liable for treating the problem.

Resolving dampness below ground level is dealt with under British Standard BS8102 Code of Practice for Protection of structures against water from the ground and you should ensure any contractor you employ works fully to this standard. The required standard of dryness in this case for habitable accommodation would be a Grade 3 standard where no leakage was acceptable, no dampness was acceptable and active measures to control internal humidity would likely be required. Clause 3.4 (b) of BS8102 states that in basements less than 4m deep the contractor has to assume a hydrostatic head of ¾ the depth of the basement, or 1m whichever is the greater. That is to say whether or not the basement was flooding prior to the contractor inspecting the basement, the contractor has to design a system that is able to cope with water should it come to bear against the basement at some point in the future.

With an existing basement it may not be practical to waterproof externally but lowering external water tables locally should be considered where able to be achieved. In any case there is a requirement that the waterproofing system should be accessible to repair as failure through some defect in the system is foreseeable given no system is perfect and attempting to dig up ground externally (even if that is possible as it may be built over) and find the source of a defect to your external waterproofing is probably impractical in most cases. That leaves structurally waterproofing an existing basement internally which you can try holding the moisture back through tanking (known as Type A systems) or letting it enter the basement and dealing with it by cavity drainage systems (known as Type C), or indeed a combination of both systems where appropriate.

You do not have to build a masonry wall internally for type C systems you can fit a cavity drainage membrane system which uses studded polyethylene or similar sheets fixed to walls that are then insulated / dry lined and usually the mebrane extends over the floors which are then covered by screeds / floating floors etc. The system then directs the moisture to floor channel drains and then to suitable drainage usually via sump pumps with non return valves, alarms, battery back-up etc.

The problem with Type A tanking where you hold the moisture back, is you can cause a shift in the moisture such that areas that were previously dry become wet and a good example would be following your newly tanked basement next doors basement suddenly starts flood and they look to you for liability. This and detachment of the tanking over time from the substrate usually as a result of poor or inappropriate substrate prep /application means the cavity drainage memebranes have found favour over recent years with those undertaking basement work though there are advantages and disadvantages with both systems to consider.

The costs you have quoted are difficult to judge without seeing the situation but relying upon the contractor to come up with their own specification for what they deem appropriate for both dry rot and dampness is asking for trouble.

In the first instance with regard to the dry rot and basement work an investigation of adjoining properties and an opening up exercise should be quoted for to determine the full extent of the issues and problems prior to you having somebody then inspect and specify for you independent of a contractor. Once such a spec is prepared this can then be issued to several competant contractors for competitive tender. The surveyors and contractors should both be CSRT and CSSW qualified for dealing with dry rot and structural waterproofing and preferably Property Care Association (PCA) / British Wood Preservation & Damp-proofing Association (BWPDA) members. Insurance backed long term guarantees should be sought though claiming upon such is not always easy.

Hope this helps - kindest regards, David Aldred independent dampness & timber surveyor

David_Aldred

Hi high_roller please look on the PCA website and on there is a heading "find a member" - select Freelance or Consultant and both will bring down lists of independent surveyors for your area - ring around and get some prices - chat to the surveyors, discuss the situation and what they can do for you, their rates and go with who you feel happy with local to you, I think there should be a couple in your area. Kindest regards, David Aldred independent dampness & timber surveyor

ANGLICANPAT

Good luck finding a PCA one in London High Roller. If you do, Id be much obliged to find out who and where they are, for my own problems. The independent I thought we might use, D Hewett MRICS of dampnessdiagnosis , I found indirectly via 'Jeff' , and his website seemed re-assuring etc, but since looking on the MSE site again today, some people are questioning 'Jeffs' thoughts on damp, which has made me nervous about using anyone who agrees with his seemingly controversial line of thought . Also this firms surveyor is MRICS , but not CSRT or a member of PCA .

One thing I dont understand when everyonesays to get a builder in first to look at damp problems. That sounds straightforward, but in our case the property is a 3 flats high semi Victorian house . Wouldnt it be a huge expensive undertaking to expect a builder to check gutters, roof ,pipework etc first yet people are saying - get a builder in for a free estimate. What builder in his right mind would do all that free? We'd be talking major scaffolding for the first two alone , and how does a builder tell visually if theres a dampcourse failure somewhere, or if theres bridging betwen brickwork , without doing some work to find out?

David_Aldred

Hi,
There are two PCA consultants listed for London itself: All Timber Infestation & Consultancy Services Ltd and Stewart Gledhill Associates.
In the home counties there are both Freelance & Consultant surveyors who give you independent qualified advice.

A builder cannot tell visually if an existing damp proof course has failed and rising dampness can only be proven by gravimetric and salt analysis tests of wall samples undertaken within a laboratory. The procedure for gravimtric tests is set out within Building Research Establishment (BRE) Digest 245. Electrical damp meters cannot prove rising dampness though they are useful tool to highlight areas of concern and at risk of decay that may not be visibly obvious.

Any external high level inspections should include photographs and video evidence that can be presented to the client to show them the problem found rather than having to take the word of those giving their findings and recommendations. Hope this helps, kindest regards, David Aldred independent dampness & timber surveyor