Dec 232014

Nothing damages a house more than water, whether it’s a leaking roof, a slow dripping pipe, or rising damp from the subsoil.

Water is the enemy of a sound house, so number one on the list of jobs when we moved in was fixing damp problems.

In our case when we moved in there were no obvious leaks, and nothing highlighted by the survey, but in living there some sources of damp soon became obvious.

Damp patch behind blocked guttering is clearly visible

Damp patch behind blocked guttering is clearly visible

The first surprise was coming down to the lounge one day and noticing the papers I’d left sitting on the sofa were wet through.  Looking up there was a hairline crack in the ceiling and water slowly dripping through.  Straight above is a small ensuite shower room so that was the obvious culprit.

I couldn’t see any problem other than a tiny hole in the waterproof mastic on the shower room floor, but bought a tube of white silicone, removed the old silicone and did the new one.  Job done and problem fixed.

Before fixing damp problems elsewhere we bought a dehumidifier.  Getting one of these is definitely a “cheat” and is no substitute for tackling the source of the damp.  But all the same the humidifier was amazing.  I couldn’t believe how much water it captured every day.

The de-humidifier we bought was a De Longhi (see reviews on Amazon) and works really really well.  It dried out the basement in less than a week, removing 5-10 litres of water a day from the air.  Since then we’ve moved it around the house to any room that feels a bit musty or has condensation on windows.  Strongly recommended!

Tell tale signs of a leak

Tell tale signs of a leak

Apart from the leaks we have worked through a whole number of other sources, and each one was quickly fixed.  The only one we needed help with was the guttering, as the roof was just too high for our ladder to reach.

The results have been amazing.  All the damp problems we had are now gone, and each was such a simple fix once found.

So, so far the damp problems have been tackled by:

  1. Fixing small leaks like the one in the shower tray
  2. Plugging the hole in the drain that let water into basement
  3. Replacing several stop cocks and gate valves on the plumbing
  4. Removing and re-tightening radiator valves that had become leaky
  5. Cleaning and unblocking the guttering
  6. Cleaning the air bricks under the house
  7. Removing old wood and newspapers from the damp crawl space
  8. Using a dehumidifier!

If you have any damp problems start with working through each possibility.  The list above is a good place to start.

Dec 222014

When you living in an older house damp is a constant threat to be kept at bay.

We’d already spent a couple of weekends fixing damp problems in the house, and I was really happy with the results.    The house has been drying out nicely, and the constant wet patches in the basement have now disappeared.

However, while checking for leaks in pipes under the lounge (there were none) a few weeks ago I noticed how damp the subsoil under there was.

A damp crawl space (the space under the floorboards) is a really common problem, but not one to ignore.

Moving rubble to avoid breaching the damp course

Moving rubble to avoid breaching the damp course

Woodworm thrives on humidity.  Anything under 70% humidity and woodworm won’t get started.  Dropping the humidity just a little lower, to around 60-65% will stop even existing woodworm from continuing to spread.  This is why modern houses, with central heating, rarely suffer from the woodworm that used to be such a threat to older houses.

First thing to do to sort out a damp crawl space is address the source of the problem.



In general damp under the floorboards can only be caused by one of three things:

1.  Poor sub-floor ventilation

2.  Rising damp from the soil

3.  Water entering from above, for example a leaking water pipe or drain.

The first of these I tackled was the easiest.  Ventilation is provided by air bricks.  These are really important, but some people seem to want to cover them up to stop cold air getting in.  Bad idea.

In our case the air bricks at the back of the house were in place, but were so clogged up with dirt, dust and old paint that no air could get in.  I chipped off all the old paint, and the iron underneath was so fragile and rusted that it disintegrated.  I’ll need to replace the brick, but for now at least they let air in.

Eli clearing under floor

Eli clearing under floor

To get air movement you  need air bricks on both sides, so I checked the front.  From outside these ones looked fine.  Clear and clean.  However as soon as I go under the house I saw the bricks were covered by the glass-fibre insulation that had been fastened under the floorboards.  Easy job.  Done.

Freeing up the air bricks alone has made a good difference.  Already the air has lost its musty smell and the ground looks drier.

But to really speed up the drying out the next job was to clear out some of the  old rubble, building waste, soil and general detritus that had been dumped under the house over the last 100 years.

All this old abandoned rubbish attracts and holds water, so needs to go.

So, this weekend, Eli and I armed with trowels, dust masks and buckets, cleared out all the old muck.  Not a pleasant job.  There was very little space to work and lots of sharp old nails and stones to get in the way.   But, very satisfying to complete.

Above are some pictures of the work.  I’m pretty confident that the space will now dry out nicely.  And just to monitor it I’ve installed a remote humidity meter so I can monitor it over time.

Piles of damp soil in the crawl space

Piles of damp soil in the crawl space