spacerspacerspacerspacerAdvertise Here
DIY Doctor
      Home   Contact   
Property Repair Systems

WELCOME TO OUR Dealing with damp PROJECT

This project is presented by Property Repair Systems

Summary: How to deal with rising damp, what to do if it happens

Share and bookmark DIY Doctor

Visit our Blog - Click Here RSS news feed DIY Doctor RSS Feed  Email Bookmark and Share


DEALING WITH RISING DAMP

A CHOICE OF METHODS

If you need any help with any type of timber repair, maintenance or damp problems, Property Repair Systems will be pleased to give you completely free, no obligation advice on 01626 331351. The information you need may be in the project below, if not, call them.

As with all DIY Doctor projects, we are totally against any solution that deals with only the effects of the problem. Get to the cause, deal with it and there will be no further effects. A cosmetic approach to rising damp, (e.g. painting over the damp or a little repointing) will only increase the expense in the long run.

What causes rising damp:

Remember, there are many other causes of damp, salt or discoloration, so check those first – see our Project – Damp: Diagnosing and Analysing.

Any masonry structure, unprotected by a properly installed damp proof course, is susceptible to natural rising damp. Moisture will rise by capillary action (a suction phenomenon arising at the boundary between moisture and a small tube, crack or other tiny, enclosed passageway known as a capillary) through the pores of the masonry, seeking a means of evaporation. The moisture will continue to rise until it reaches a height where, unless no evaporation is possible, gravity takes over and pulls it down again. This height is seldom more than 1.20m, although deposits of ‘salts’ may be found higher in the wall, often driven there by the use of non-breathing plasters, renders, ‘tanking’, paints or vinyl wall papers.

What is damp proofing
Damp proofing at ground level is the provision of a barrier across the whole width and length of a wall, which cuts off the capillary supply of moisture naturally rising from the ground.  In external walls, to avoid rain water splashing up above the damp proof course, the DPC (damp proof course) has to be positioned at least 6 inches (150mm) above the outside ground (Building Regulations and British Standard 6576).

What types of barrier can be used
Historically, a variety of materials have been installed during the building process – stone, slate, lead, zinc and stainless steel and more recently (and currently) plastic.
However, once a building has been erected it is more difficult to insert a physical DPC (although stainless steel sheet can be vibrated into walls, via saw cut slots), so other methods have been developed for remedial action;

  • Water repellent – liquid, paste, gel, or cream by injection – amateur and professional
  • Pore blocking – cement based mortar, by injection – mainly professional
  • Osmotic – passive or active, via embedded wires – mainly professional
DPC Ultra Cure Cream
Buy DPC Ultra Cure cream with a large 1 litre skeleton gun – quick and clean
   
Renderproof
Buy Renderproof  to mix in the sand and cement barrier coats, to hold back ‘salts’
   
Mesh Membrane
Buy Mesh Membrane, instead of using sand and cement render, then plaster or plasterboard

 

How these are installed

  • Water repellent – holes, usually between 10-12mm in diameter, are drilled either into the mortar joints or via the bricks or stones and the chemical is injected using a high pressure pump (liquids) or low pressure hand pump or skeleton gun (creams, pastes and gels). The chemicals spread through the damp masonry, over a period of several months, to join up and form a continuous water repellent layer. This is NOT a solid vapour barrier – it prevents further liquid water from passing through, thus allowing the wall to dry out.
  • Pore blocking – the cement based injection mortar is mixed with water to form a ‘slurry’ and injected from a re-usable, plastic bodied, heavy duty ‘gun’. It rapidly sets, giving off great heat, to form a solid plug in the wall. The holes are generally 18-20mm in diameter and this method is only really suitable for thick, stable stone walls. The injected mortar then slowly generates impermeable ‘salts’, which over several months block the pores in the wall and prevent moisture from rising. This method requires large drilling machines, expensive drill bits and mortar guns, making it uneconomic for amateur use.
  • Osmotic – the old, ‘passive’ system used copper wires, which unfortunately corroded, but the latest Lectros Active System utilises a titanium wire, connected to a special mains powered control box, which is run around the walls rather like a ring main. Bent at regular intervals to form anodes, the wire loops are inserted into large holes drilled into the wall (internally, externally or both if necessary). The wire is hidden in formed "chases" or existing, raked out brickwork joints and the whole system is earthed. The electricity from the mains supply passes through a transformer, through the anodes and to earth, setting up an electrical field, which repels the damp. The holes are filled with a special mortar, to ensure good conductivity. This method requires large drilling machines, expensive drill bits and special mortars, making it uneconomic for amateur use

What if my walls are not brick
The modern injection cream products perform well in all types of wall and unlike the older liquid injection methods the slow release of a uniform amount of cream per hole ensures good spread between holes and a reliable result.

How "painful" is installation:

Installation using DPC cream based products is neat and very quick. A series of small holes (10-12mm diameter) are drilled at least 6 inches (150mm) above ground level (exterior walls), the chemical is injected, the holes filled and the result almost invisible. In some cases, the plaster can even stay on the wall, if it can be seen to be sound. It must be remembered however, that rising damp will probably have brought water soluble salts into the plasterwork and these hygroscopic salts will still attract moisture from the atmosphere, even after the wall itself has dried out. Care must be taken to minimize the effect of the residual salts. Sometimes Salt Neutraliser liquid can deal with minor patches of ‘salt’, if the plaster is otherwise solid.

For more technical information, product costing's or the name of your nearest qualified Contractor go to Property Repair Systems

Why not check out our video sections on "damp proof injection" and "rising damp" to watch some films on how to deal with rising damp.


Property Repair Systems


Much more construction information is available in our bookstore. All the tools and fittings you need in the toolstore.





Forums





Are you a tradesman ? Get your very own webpage with ProblemSolved all for FREE - Click here



Share and bookmark DIY Doctor

Link to DIY Doctor - Click Here RSS news feed DIY Doctor RSS Feed  Email Bookmark and Share


Damp and damp proofing
Post new topic
 Topics   Replies   Author   Views   Last Post 
No new posts Damp on wall in doorway with UPVC door
0 carolinem 31  
carolinem View latest post
No new posts Buying first house with damp course warranty running out
0 Hails 37  
Hails View latest post
No new posts How to remove mould from damp wall & floor from sofa fab
0 BarberJoh 81  
BarberJoh View latest post
No new posts Damp within internal chimney/wall - Please help!
2 charlied 191  
charlied View latest post
No new posts Bad Condensation And Damp Problem
4 Bimbovelo 577  
stoneyboy View latest post
No new posts recently plastered and painted kitchen walls,flaking paint
1 james smi 170  
rosebery View latest post
No new posts Earth floor
2 Jeffx 154  
rosebery View latest post
No new posts Damp under floorboards
1 hymercat 223  
stoneyboy View latest post
No new posts Mystery Damp Problem - Health Issues? : Help Needed!
0 nickgrc 153  
nickgrc View latest post
No new posts render over dpc
0 chrisbpt 190  
chrisbpt View latest post
No new posts Mysterious Red Dust
1 kaks 346  
Shadow View latest post
No new posts Damp chimney breast
0 JanetP 193  
JanetP View latest post
No new posts damp proof membrane
0 Firkin 235  
Firkin View latest post
No new posts kitchen walls moulded do i dryline
0 catson 260  
catson View latest post
No new posts Mouldy Carpet Under Skirting Boards
1 *Gill* 492  
stoneyboy View latest post
No new posts Condensation problem
1 scifo 1189  
scifo View latest post
No new posts Is it rising damp and how much is it likely to cost?
0 conormcm 646  
conormcm View latest post
No new posts damp/wet around hearth.
0 sfallon 267  
sfallon View latest post
No new posts Damp behind skirting boards
0 AJG 412  
AJG View latest post
No new posts damp, condensation, mould
1 tashne26 1102  
bd3cc View latest post
No new posts Strange damp patch
0 mblago 418  
mblago View latest post
No new posts shed floor problem - is this a solution?
0 cookie_bo 257  
cookie_bo View latest post
No new posts Damp ground in cavity under house
2 SScyner 531  
SScyner View latest post
No new posts Damp Patches
1 r16chh 608  
stoneyboy View latest post
No new posts Damp wall in entry
0 madstaff 217  
madstaff View latest post
No new posts Foil backed plaster board for mould mildew
3 daztc 722  
Dan the m View latest post
No new posts Damp Proofing - wall damae amount?
0 smallclon 324  
smallclon View latest post
No new posts What are the conditions supposed to be under floorboards?
2 deborah75 712  
acsimpson View latest post
No new posts Do I need to install a damp course ?
1 bluenose 546  
stoneyboy View latest post
No new posts Internal Wall Damp
2 zammir_al 1209  
zammir_al View latest post
No new posts Lowering ground level with trench - how wide?
2 peelypost 452  
peelypost View latest post
No new posts I cant find the damp!
11 sian 2424  
Perry525 View latest post
No new posts Internal wall damp - Radiator leak?
3 lardy2001 586  
Dan the m View latest post
No new posts damp problem over the chemical damp coure membrane
3 aness 827  
Perry525 View latest post
No new posts My damp course guarantee
3 horton090 648  
horton090 View latest post
No new posts Tanking in a kitchen
0 mrowen 423  
mrowen View latest post
No new posts Shower wall water infiltration: Will dehumidifier help?
2 shababak 562  
The Rotte View latest post
No new posts Would Basement Extractor Fan Work?
1 burt12345 419  
stoneyboy View latest post
No new posts Why does it still look wet?
1 ormy 627  
bd3cc View latest post
No new posts Damp On Party Wall
0 Miss Mar 858  
Miss Mar View latest post
No new posts black mould on wall and ceiling
0 fergienes 1311  
fergienes View latest post
No new posts New wardrobe damp proofing
0 Darkmatte 577  
Darkmatte View latest post
No new posts Damp concrete floor
0 Aero 940  
Aero View latest post
No new posts damp chimney wall
0 jimandton 771  
jimandton View latest post
No new posts crumbling plaster post damp proofing
1 jennylc 655  
stoneyboy View latest post
No new posts Damp Garage
1 aeyres 473  
stoneyboy View latest post
No new posts damp issues in new house
1 markwilli 764  
Perry525 View latest post
No new posts my house smells of damp
1 gee 1496  
Perry525 View latest post
No new posts Internal damp patches
1 p.bedford 1269  
stoneyboy View latest post
No new posts Verical damp proofing
0 facelift 504  
facelift View latest post
Display topics from previous:  
Post new topic     -> Damp and damp proofing
Jump to:  
     
     
  
Search Diy Doctor

Related projects
#



© Copyright Diydoctor Ltd 2009  Developed by Boson Media  Hosted by Rackspace