Water, Drainage and Ventilation
Designing new schemes
Subject to archaeological advice, we recommend routing pipes underground rather than directly through walls.
If you are thinking about installing new toilets, composting or macerating lavatories can remove or reduce the need for drainage trenches.
In rural buildings where use is not heavy and where space allows, you may be able to consider a trench arch system, which can avoid deep excavation and complex drainage. You can find information about our recommendations for considering trench arch systems and the impact these systems can have on archaeological remains in churchyards.
This includes the following points:
- Wherever feasible, it's preferable to connect to mains drains if you have access to these, although making this connection may also have archaeological implications.
- If you are considering a trench arch system, we recommend you undertake an archaeological assessment of the potential of the churchyard at an early stage. This will ensure that you can take the information it reveals into account when developing the specification.
- The assessment should consider whether you need archaeological fieldwork, like evaluation, before you get permission or begin works.
- Trench arch drains are best located away from archaeologically sensitive areas of the church. Such avoidance is made possible by understanding the archaeological potential of the site.
- You should not assume that you will not find significant archaeological remains within the top 0.5 metres, just because this is above current burial depth.
It is often possible to provide ventilation for toilets and kitchens discreetly. For example, in the upper stages of towers, by introducing mesh grilles into windows or flush cast-meal or stone-tile grilles into walls, or by setting the vent-pipe back in the wall and fitting stone or slate louvres.
We recommend that you avoid drilling new ducts through historic masonry and installing external fan units and cowls.
A degree of dampness is common in the walls of old churches, especially where external ground levels have risen over time.
If you are considering work to remedy damp, we do not normally recommend ground lowering, which is sometimes associated with laying drains. This is because ground lowering can damage archaeological features, foundations and wall surfaces, and may lead to excessive drying out with subsequent cracking and even subsidence.
The best way for you to manage damp is by regularly clearing gutters and downpipes, ensuring good ventilation and allowing for permeability in the wall surfaces through the use of 'breathable' mortars, plasters and finishes. The best way to get rainwater away from your building is through downpipes to gulleys and soakaways, which keep water away from the walls of the building.
Please also see our pages for more information on maintenance.