The Crime Prevention Website


The following paragraphs deal with sheds, summerhouses, greenhouses and conservatories, all of which have different crime risks attached to them and different security solutions.

Sheds, including summerhouses and other timber and steel garden buildings  

The majority of sheds are constructed from timber and can be secured to a reasonable level at least to a point where the thief has to bring house breaking tools to affect an entry.  It is important to realise that we are not just trying to prevent theft from the shed and other outbuildings; we are also trying to stop the thief from accessing garden tools with which to break into your house or flat.

This website's Home Security Survey results (August 2017) reveal that:

  • 14% of sheds are 'very well' secured
  • 47% of sheds are 'Quite well' secured
  • 39% of sheds are 'Not that well' secured

This finding is not a good finding since one in three households have a shed that is easy to break into.  In fact some of these poorly secured sheds won't even have a lock.

These days more and more of us are using our garden outbuildings as an extension of our homes for things like offices, games rooms, gyms and (like some of my friends) bars!  This simply means there is yet more property to steal from buildings that don’t generally have the best security.

Shed doors – thick ones 

A large, quality constructed shed is likely to have doors that are at least 44mm thick and can therefore take a BS 3621 mortice sashlock.  So check to see if your sashlock carries the kitemark and change it if it doesn’t.  If you have 44mm thick double doors then you need to install mortice security bolts into the top and bottom rails of the second opening leaf so that they bolt into the top and bottom door frames. Fitting them at 90° to the grain of the wood helps to prevent the timber from splitting under force.  Keep and use the tower bolts on the second opening door leaf; it all helps. Pay particular attention to ‘T’ hinges, if you have them, as it may be possible to unscrew them and take the door off from the hinge side. Rather than change the hinge it is a good idea to refit them using coach bolts.  Make sure that you screw the nut over a washer to prevent the bolt pulling through the wood.  In addition, or instead, you can fit a pair of hinge bolts to each leaf, which will hold the door in place should someone try and undo the hinges.  Also make sure that the hinge pins cannot be driven through the hinge or even lifted out with the fingers and change the hinges if this is possible, although by fitting hinge bolts you will obviate this need. (See  Door security Door locks, hardware and fittings )

Shed doors – thin ones

If you have a little shed - a potting shed, then the chances are the door will be of the ledged and braced type.  There’s nothing wrong with that, but you won’t be able to use a mortice lock.  This type of door should instead be locked with a hasp, staple and padlock.  For a stronger fitting use coach bolts instead of screws and make sure you fit the hasp and staple the right way round whereby the hasp, when closed, conceals the fixings (I’ve seen it the wrong way round lots of times!).   Fit the hasp and staple through the timber frames, not the tongue and groove boards.  Alternatively, you can fit a padbolt, which is normally supplied with coach bolts.  If you are bit handy then bolting the fittings through a small steel plate fixed to the inside face of the door will provide an even stronger fit.  Also, secure the ‘T’ hinges with coach bolts as described in the previous paragraph.  (See Preventing theft from the garden,  Padlocks in this section)  

Shed windows – non opening

Little sheds will often have non opening windows and whether you need to add security will depend on what you keep in it.  If you do need to improve security then simply fix a purpose made grille on the inside or to keep the cost down use a sheet of welded mesh and fix it in place with lengths of timber cut to fit over and screwed into the window frame.  If you don’t want people to see what you’ve got in the shed hang a net curtain or use a reflective film on the inside of the glazing. 

Shed windows – opening 

Larger sheds will probably have opening windows which should be fitted with window locks at the very least.  (See  Window security )  As with non-opening shed windows they can also be fitted with grilles and welded mesh sheeting on the inside and it is a good idea to hang nets or use reflective film on the glazing to prevent the thief seeing what there is to steal. 

Shed walls

I am not suggesting you improve the security of the shed walls, because in all the years in the police I don’t think I ever saw a shed broken into via the walls, or am I tempting fate?  That said, lots of people like me, who work from home in the shed at the bottom of the garden, have insulated their sheds with additional timber sheeting, such as plywood, on the inside of the walls with insulating material in between.  By chance this has obviously made my shed quite secure; and with its own alarm system and grilles on the windows it would be quite a task to break into it without me or a neighbour knowing about it.  (See Personal security,  Computers )

Security inside the timber outbuilding   

To add some additional security inside the shed for things like power tools and chemicals you can buy steel containers from DIY outlets and fix them onto the floor through the floor joists using long screws or into the concrete base using expandable bolts.  To further add to the inconvenience of the burglar you can also pass a heavy duty chain through the handles of the spade, shovel and fork and padlock the chain to an anchor plate fitted to the floor.  Bicycles can also be secured inside the shed in the same way.  You can also buy cable alarms in a similar way, which set off an alarm if they are cut.  (See  Bicycles and Vehicles, Bicycles )    

Steel garden sheds and workshops

Steel buildings can be assumed to be more secure than timber buildings, but the security can always be improved still further by adding additional locks to the doors and grilling the windows.  It all rather depends on what you keep in the building. 


Some people I know lock their greenhouses because they grow prize vegetables and use expensive heating equipment during the winter, but by and large these types of buildings are simply not that secure and shouldn’t be used to store anything of great value or the garden tools.  Most timber and metal framed greenhouses will have a staple on the door through which you can pass a small padlock, but that’s about it.  They are not that suitable for alarms (except maybe a simple contact operated shed alarm), because of the huge range of temperatures inside them and so it is advised that you at least locate the building where it can be seen from the house.

Updated December 2015, August 2017